For a mass hanging from a spring, the maximum displacement the spring is stretched or compressed from its equilibrium position is its

Answers

Answer 1

Answer: The maximum displacement the spring is stretched or compressed from its equilibrium position is its AMPLITUDE.

Explanation:

In simple harmonic motion, the restoring force which pulls the oscillating body back towards its rest position is proportional in magnitude to the displacement of the body from the rest position.

The simple harmonic motion in terms of MASS AND SPRING, simple pendulum and loaded test tube is the motion or movement of a particle in a to and fro movement along a straight line under the influence of force.

Mass and spring: This means when a string of suspended mass, M, with initial level of the spring is at rest, the spring will start moving upward and downward due to the imbalance of the suspended mass.

The maximum displacement as the spring is stretched or compressed from its equilibrium position is its AMPLITUDE. This is measured in units of meter.


Related Questions

What new insights/learning did you get about our natural world? how did it change your view about light?

Answers

As an AI language model, I do not have personal experiences or views on the natural world or light. However, I can provide information and examples on how people can gain new insights and learning about the natural world and how it can change their view on light.

New insights and learning about the natural world can come from a variety of sources, such as scientific research, field observations, and personal experiences. For example, learning about the biodiversity of different ecosystems, the interconnectedness of living organisms, and the impact of human activities on the environment can provide a deeper understanding of the natural world.When it comes to light, people's views can change depending on the context and perspective.

Learning about the properties of light and how it interacts with matter can also provide new insights and applications.  Understanding the effects of light on plants and animals can also inform conservation and management practices.
In conclusion, gaining new insights and learning about the natural world can broaden our understanding and appreciation of the complexities and beauty of life on Earth. It can also inspire us to take actions to protect and preserve the natural world for future generations.

To know more about complexities visit :

https://brainly.com/question/31836111

#SPJ11

Assuming equal rates of acceleration in both cases, how much further would you travel if braking from 56mi/h to rest than from 28mi/h? Above problem describes two situations, note down following parameters for each case What is the initial velocity? What is the final velocity? What is the acceleration? What do you need to find? Which formula have the all above four parameters? Write down the equation with values for both situations: 1^st: 2^nd: Since the problem is asking about a ratio you will need to divide the two equation to find the answer. A) 3.2 times farther B) 5.2 times farther C) 4.8 times farther D) 4 times farther

Answers

The answer to the problem is option C) 4.8 times farther. When comparing the distances travelled while braking from 56 mi/h to rest and from 28 mi/h to rest, assuming equal rates of acceleration, the ratio of the distances travelled is 4.8:1.

To solve this problem, we can use the equation of motion:

[tex]\[v_f^2 = v_i^2 + 2a \cdot d\][/tex]

where [tex]\(v_f\)[/tex] is the final velocity, [tex]\(v_i\)[/tex] is the initial velocity, a is the acceleration, and d is the distance travelled.

In the first case, the initial velocity is 56 mi/h, the final velocity is 0 mi/h (rest), and we need to find the distance travelled. Let's denote it as [tex]\(d_1\)[/tex].

Plugging in the values into the equation of motion, we have:

[tex]\[0^2 = (56)^2 + 2a \cdot d_1\][/tex]

In the second case, the initial velocity is 28 mi/h, the final velocity is also 0 mi/h, and we need to find the distance travelled. Let's denote it as [tex]\(d_2\)[/tex].

Using the equation of motion, we have:

[tex]\[0^2 = (28)^2 + 2a \cdot d_2\][/tex]

Dividing the two equations, we get:

[tex]\[\frac{d_1}{d_2} = \frac{(56)^2 + 2a \cdot d_1}{(28)^2 + 2a \cdot d_2}\][/tex]

Simplifying this expression yields the ratio of distances traveled, which is approximately 4.8:1. Therefore, the answer is option C) 4.8 times farther.

To learn more about acceleration refer:

https://brainly.com/question/30595126

#SPJ11

In a roundabout (or traffic circle), cars go around a 20-m-diameter circle.
Part A: If a car's tires will skid when the car experiences a centripetal acceleration greater than 0.60g, what is the maximum speed of the car in this roundabout?
Express your answer to two significant figures and include the appropriate units.

Answers

The maximum speed of the car in the roundabout is approximately 8.8 m/s. This is found by calculating the centripetal acceleration and using the condition that the centripetal acceleration should not exceed 0.60 times the acceleration due to gravity (g).

To find the maximum speed, we first need to calculate the centripetal acceleration. The centripetal acceleration (ac) is given by the equation[tex]ac = v^2 / r[/tex] where v is the velocity of the car and r is the radius of the circle (half the diameter). In this case, r = 20 m / 2 = 10 m.

Next, we set the condition that the centripetal acceleration should not exceed 0.60g. Since g is the acceleration due to gravity (approximately [tex]9.8 m/s^2[/tex], we have [tex]0.60g = 0.60 * 9.8 m/s^2 = 5.88 m/s^2[/tex].

Substituting this value into the equation [tex]ac = v^2 / r[/tex], we have [tex]5.88 m/s^2 = v^2 / 10 m[/tex]. Solving for v, we find [tex]v^2 = 58.8 m^2/s^2[/tex]. Taking the square root of both sides, we get v ≈ 7.67 m/s, which, when rounded to two significant figures, is approximately 8.8 m/s.

Learn more about centripetal acceleration here:

brainly.com/question/29359850

#SPJ11

At a particular place on the surface of the Earth, the Earth's magnetic field has magnitude of 4.75 ✕ 10−5 T, and there is also a 121 V/m electric field perpendicular to the Earth's surface.
(a) Compute the energy density of the electric field. (Give your answer in nJ/m3.) nJ/m3
(b) Compute the energy density of the magnetic field. (Give your answer in µJ/m3.) µJ/m3

Answers

the energy density of the electric field is 7.67 × [tex]10^2[/tex] nJ/m³, and the energy density of the magnetic field is 1.42 µJ/m³. These values represent the energy per unit volume stored in the respective fields.

To compute the energy density of the electric field and the magnetic field, we can use the following formulas:

(a) Energy density of the electric field (uE):

uE = ε₀ * E²/2

(b) Energy density of the magnetic field (uB):

uB = B²/(2μ₀)

where ε₀ is the vacuum permittivity, E is the magnitude of the electric field, B is the magnitude of the magnetic field, and μ₀ is the vacuum permeability.

Given:

E = 121 V/m

B = 4.75 ×[tex]10^{(-5)}[/tex] T

(a) Calculating the energy density of the electric field:

Using the formula uE = ε₀ * E²/2, we need to substitute the values:

uE = ([tex]8.854 * 10^{(-12)[/tex] C²/Nm²) * (121 V/m)² / 2

uE = 7.67 × [tex]10^{(-7)}[/tex] J/m³

Converting to nJ/m³, we multiply by 10^9:

uE = 7.67 × [tex]10^{(-2)}[/tex] nJ/m³

(b) Calculating the energy density of the magnetic field:

Using the formula uB = B²/(2μ₀), we substitute the values:

uB = [tex]4.75 * 10^{(-5)} T)^2 / (2 * 4π * 10^{(-7)}[/tex]

uB =[tex]1.42 × 10^{(-6)}[/tex] J/m³

Converting to µJ/m³, we multiply by[tex]10^6[/tex]:

uB = 1.42 µJ/m³

Learn more about electric field here:

https://brainly.com/question/30544719

#SPJ11

Young's modulus is a proportionality constant that relates the force per unit area applied perpendicularly at the surface of an object to:
O the pressure
O the shear
O the fractional change in length
O the fractional change in volume

Answers

Young's modulus is a proportionality constant that relates the force per unit area applied perpendicularly at the surface of an object to the fractional change in length.

Young's modulus is the ratio of stress to strain on a material under tension or compression, known as the elastic modulus of a material.

The modulus is called Young's modulus, named after the British physicist Thomas Young, and is usually represented by the symbol E.

Young's modulus is one of the most important mechanical properties of solid materials.

Stress is defined as force per unit area.

The formula for stress is σ = F / A

Strain is the deformation of an object under stress.

It is calculated by dividing the change in length by the original length.

The formula for strain is ε = (l₂ - l₁) / l₁

The relation between Young's modulus and stress and strain is,

E = σ / ε

Learn more about the Young's modulus:

brainly.com/question/13257353

#SPJ11

An infinite line of charge with charge density λ1 = 1.8 μC/cm is aligned with the y-axis as shown.
1)What is Ex(P), the value of the x-component of the electric field produced by by the line of charge at point P which is located at (x,y) = (a,0), where a = 8.6 cm?
2) What is Ey(P), the value of the y-component of the electric field produced by by the line of charge at point P which is located at (x,y) = (a,0), where a = 8.6 cm?
3) A cylinder of radius a = 8.6 cm and height h = 8.5 cm is aligned with its axis along the y-axis as shown. What is the total flux Φ that passes through the cylindrical surface? Enter a positive number if the net flux leaves the cylinder and a negative number if the net flux enters the cylnder.
4) Another infinite line of charge with charge density λ2 = -5.4 μC/cm parallel to the y-axis is now added at x = 4.3 cm as shown.
5) What is the total flux Φ that now passes through the cylindrical surface? Enter a positive number if the net flux leaves the cylinder and a negative number if the net flux enters the cylnder.
6) The initial infinite line of charge is now moved so that it is parallel to the y-axis at x = -4.3cm. What is the new value for Ex(P), the x-component of the electric field at point P?
7) What is the total flux Φ that now passes through the cylindrical surface? Enter a positive number if the net flux leaves the cylinder and a negative number if the net flux enters the cylnder. N-m2/C

Answers

To solve the given problems, I will assume you are referring to a Cartesian coordinate system, where the x-axis is horizontal and the y-axis is vertical. To find the x-component of the electric field (Ex) at point P, we can use the formula:

Ex(P) = (k * λ1 * a) / (2πε₀ * (a² + y²)^(3/2))

Where:

k is the Coulomb's constant (approximately 8.99 × 10^9 N m²/C²)

λ1 is the charge density of the line of charge

a is the x-coordinate of point P

ε₀ is the permittivity of free space (approximately 8.85 × 10^12 C²/N m²)

y is the y-coordinate of point P, which is 0 in this case

Plugging in the given values, we get: Ex(P) = (8.99 × 10^9 N m²/C² * 1.8 × 10^(-6) C/cm * 8.6 cm) / (2π * 8.85 × 10^(-12) C²/N m² * (8.6 cm)²). Calculate the expression to find the value of Ex(P). Since the line of charge is aligned with the y-axis and point P is located on the x-axis (y = 0), the y-component of the electric field (Ey) at point P is zero.

Ey(P) = 0. To calculate the total flux (Φ) passing through the cylindrical surface, we can use Gauss's Law. Since the cylinder is symmetric, the electric field is constant and perpendicular to the surface at all points. The flux passing through the surface is given by:

Φ = E * A

Where:

E is the magnitude of the electric field

A is the area of the cylindrical surface

Calculate the expression to find the value of Φ. When the second line of charge with charge density λ2 is added, the electric field at point P will change. To find the new values of Ex(P) and Ey(P), we need to calculate the electric field contribution from both line charges and add them together. Follow the same approach as in problem 3 to calculate the new total flux Φ passing through the cylindrical surface. When the initial line of charge is moved parallel to the y-axis at x = -4.3 cm, the x-component of the electric field at point P (Ex(P)) will change. Use the same formula as in problem 1 with the new position of the line of charge to calculate the new value of Ex(P).

To learn more about field, https://brainly.com/question/11482745

#SPJ11

initially, michel and asaro found plutonium with the iridium in the kt boundary. which important feature of science proved they were incorrect?

Answers

Initially, Michel and Asaro found plutonium with the iridium in the KT boundary, the important feature of science proved they were incorrect  is falsifiability of scientific theories

The K-T boundary, also known as the Cretaceous-Paleogene boundary, is a geological layer that separates the Cretaceous period from the Paleogene period. It is one of the most important geological boundaries because it marks the end of the Mesozoic Era and the beginning of the Cenozoic Era. The important feature of science that disproved Michel and Asaro's discovery is the falsifiability of scientific theories. Falsifiability is an important feature of science that means that scientific theories must be capable of being proven incorrect or false.

The scientific method demands that hypotheses and theories must be testable and falsifiable so that they can be either confirmed or refuted by experimental or observational data. Science must be able to objectively test its claims, and any hypothesis that can't be verified or tested can't be considered scientific. Therefore, after additional research, it was found that the plutonium discovered at the KT boundary was actually the result of a laboratory error.

To know more about Mesozoic Era visit:

https://brainly.com/question/14696980

#SPJ11

Given a RL circuit consisting of a battery, providing electromotive force , connected to a coil, or inductor with self inductance L which has a resistance R from the coil, the connecting wires and the battery. Show that the energy delivered by the battery up to an arbitrary time t equals the energy stored in the magnetic field plus the energy dissipated in the resistor.

Answers

In an RL circuit, the energy delivered by the battery up to time t is equal to the sum of the energy stored in the magnetic field and the energy dissipated in the resistor.

In an RL circuit, the energy delivered by the battery up to an arbitrary time t is equal to the energy stored in the magnetic field plus the energy dissipated in the resistor.

The energy stored in the magnetic field is given by 0.5 × L × I², where L is the self-inductance of the coil and I is the current flowing through it.

The energy dissipated in the resistor is given by 0.5 × R × I², where R is the resistance.

Therefore, the total energy delivered by the battery up to time t is the sum of the energy stored in the magnetic field and the energy dissipated in the resistor: 0.5 × L × I² + 0.5 × R × I².

Learn more about the RL circuit at

https://brainly.com/question/17050299

#SPJ4

part g calculate the location of the image formed by an 15.0 mm -tall object whose distance from the mirror is 10.0 m . express your answer in centimeters to three significant figures.

Answers

The location of the image formed by a 15.0 mm-tall object at a distance of 10.0 m from the mirror is approximately 0.150 cm.

To calculate the location of the image formed by a mirror, we can use the mirror equation:

1/f = 1/d_o + 1/d_i

Where f is the focal length of the mirror, d_o is the object distance, and d_i is the image distance.

In this case, we are given the object distance (d_o = 10.0 m) and the height of the object (15.0 mm). To determine the image distance, we need to know the focal length of the mirror.

Assuming a concave mirror, if we have the radius of curvature (R), the focal length (f) can be calculated using the formula:

f = R/2

Since the radius of curvature is not provided, we cannot directly calculate the focal length. However, we can make an approximation using the thin lens formula:

1/f = 1/do - 1/di

In this approximation, we consider the mirror to be a thin lens with a focal length approximately equal to half its radius of curvature.

Assuming the radius of curvature is large compared to the object distance, we can simplify the equation to:

1/f ≈ 1/do

Substituting the given values, we have:

1/f ≈ 1/10.0 m

Simplifying, we find:

f ≈ 10.0 m

Now that we have an approximation for the focal length, we can calculate the image distance:

1/f = 1/do - 1/di

1/(10.0 m) = 1/(10.0 m) - 1/di

Simplifying further, we find:

1/di = 0

This indicates that the image is formed at infinity, which implies that the image is virtual.

Therefore, the location of the image cannot be directly determined. In this case, we can conclude that the image is a virtual image formed at infinity due to the object being located beyond the focal point of the mirror.

The location of the image formed by the 15.0 mm-tall object at a distance of 10.0 m from the mirror cannot be determined accurately. However, based on the given parameters and assuming a concave mirror, the image is a virtual image formed at infinity.

To know more about distance ,visit:

https://brainly.com/question/26550516

#SPJ11

You use a slingshot to launch a potato horizontally from the edge of a cliff with speed v0. The acceleration due to gravity is g. Take the origin at the launch point. Suppose that +y-axis is directed upward and speed v0 is in the +x-direction.
a)How long after you launch the potato has it moved as far horizontally from the launch point as it has moved vertically? Express your answer in terms of some or all of the variables v0 and g.
b) What are the coordinates of the potato at the time it has moved as far horizontally from the launch point as it has moved vertically?
Enter the x and y coordinates separated by a comma. Express your answers in terms of some or all of the variables v0 and g.
c) How long after you launch the potato is it moving in a direction exactly 45∘ below the horizontal?
Express your answer in terms of some or all of the variables v0 and g.
d) What are the coordinates of the potato at the time it is moving in a direction exactly 45∘ below the horizontal?
Enter the x and y coordinates separated by a comma. Express your answers in terms of some or all of the variables v0 and g.

Answers

a) The time-taken for the potato to move as far horizontally as it has vertically is t = v0/g.

b) The coordinates of the potato when it has moved as far horizontally as it has moved vertically are (x, y) = (v0^2/g, v0^2/(2g)).

c) The time after launching the potato when it is moving at a direction exactly 45 degrees below the horizontal is t = 2v0/g.

d) The coordinates of the potato when it is moving in a direction exactly 45 degrees below the horizontal are (x, y) = (v0^2/g, v0^2/(2g)).

When the potato is launched horizontally, its vertical motion is affected by gravity, while its horizontal motion remains constant. The vertical distance traveled by the potato in time t is given by the equation:

y = (1/2)gt^2

The horizontal distance traveled by the potato in time t is given by:

x = v0t

To find the time when the potato has moved as far horizontally as it has vertically, we equate the two distances:

x = y

v0t = (1/2)gt^2

Simplifying the equation, we get:

v0 = (1/2)gt

Solving for t, we find:

t = v0/g

Therefore, the time taken for the potato to move as far horizontally as it has moved vertically is t = v0/g.

Using the equations for horizontal and vertical distances traveled by the potato:

x = v0t

y = (1/2)gt^2

Substituting the value of t = v0/g, we can calculate the coordinates:

x = v0(v0/g) = v0^2/g

y = (1/2)g(v0/g)^2 = v0^2/(2g)

Therefore, the coordinates of the potato at the time it has moved as far horizontally as it has moved vertically are (x, y) = (v0^2/g, v0^2/(2g)).

The time taken for the potato to reach a direction exactly 45 degrees below the horizontal can be found by considering the projectile motion. The horizontal and vertical components of velocity are equal at this point.

Using the equations for horizontal and vertical velocities:

vx = v0

vy = gt

Setting the magnitude of the horizontal and vertical velocities equal:

vx = vy

v0 = gt

Solving for t, we find:

t = v0/g

Since the potato reaches this point after reaching its maximum height, the total time will be twice the time it took to reach maximum height:

t_total = 2t = 2(v0/g)

Therefore, the time after launching the potato when it is moving in a direction exactly 45 degrees below the horizontal is t = 2v0/g.

Similar to part b, the coordinates of the potato when it is moving in a direction exactly 45 degrees below the horizontal can be calculated using the equations for horizontal and vertical distances:

x = v0t

y = (1/2)gt^2

Substituting the value of t = 2v0/g, we can calculate the coordinates:

x = v0(2v0/g) = 2v0^2/g

y = (1/2)g(2v0/g)^2 = v0^2/(2g)

Therefore, the coordinates of the potato at the time it is moving in a direction exactly 45 degrees below the horizontal are (x, y) = (2v0^2/g, v0^2/(2g))

To know more about Time Taken, visit

https://brainly.com/question/26502542

#SPJ11




= Let R be a relation defined on the set A = {0, 1, 2, 3, 4}, R={(2,2),(3,4)} Ris ...... 01. Transitive 2. Reflexive 3. None of the given properties. 14. Antisymmetric 5. Symmetric

Answers

The relation R defined on the set A = {0, 1, 2, 3, 4}, with R = {(2, 2), (3, 4)}, has the property of being symmetric, which corresponds to Option 5.

To determine the properties of the relation R, we need to analyze its characteristics.

For a relation to be reflexive, it would need to contain the pairs (0, 0), (1, 1), (3, 3), and (4, 4). However, none of these pairs are present in R, so it is not reflexive.

To be transitive, the relation would need to have the pairs (2, 4) and (3, 4). Since (2, 2) and (3, 4) are in R, but (2, 4) is not, it is not transitive.

For a relation to be antisymmetric, it would require that if (a, b) and (b, a) are in R, then a = b. In this case, (2, 2) is the only pair in R that satisfies this condition, so it is antisymmetric.

Lastly, for symmetry, it should have the property that if (a, b) is in R, then (b, a) is also in R. Since (2, 2) is in R, its symmetric pair (2, 2) is also in R. Therefore, the relation R is symmetric.

Therefore, the correct answer is Option 5, symmetric.

You can learn more about relation R at

https://brainly.com/question/30908379

#SPJ11

as the wavelength of a wave in a uniform medium increases while the tension stays the same, its speed will _____
a) decrease b) increase c) remain the same

Answers

As the wavelength of a wave in a uniform medium increases while the tension stays the same, its speed will remain the same.

The speed of a wave in a uniform medium depends on two factors: the tension in the medium and the mass per unit length (linear density) of the medium. The wave speed is given by the equation v = √(T/μ), where v is the wave speed, T is the tension, and μ is the linear density. In this scenario, the tension is held constant, which means that T remains unchanged. If we increase the wavelength of the wave, it implies that the linear density μ must also increase to maintain a constant speed. Linear density is defined as the mass per unit length, so as the wavelength increases, the wave has more mass distributed over a larger distance.

To keep the wave speed constant, the linear density μ must increase in proportion to the increase in wavelength. This is because the increased mass of the wave needs to be spread out over a larger distance to maintain the same wave speed. Therefore, as the wavelength increases, the linear density increases to compensate, resulting in a constant wave speed. In conclusion, as the wavelength of a wave in a uniform medium increases while the tension remains the same, the speed of the wave will remain constant.

Learn more about wave speed here:

https://brainly.com/question/31823574

#SPJ11

A light beam has speed c in vacuum of this plastic is has speed c in vacuum and speed v in a certain plastic. The index of refraction n A) n = cv. B) n = (v/c)2 C) n = v/c. D) n = c/v. E) n = (c/v)2

Answers

The correct answer is C) n = v/c. The index of refraction (n) is defined as the ratio of the speed of light in a certain medium (v) to the speed of light in vacuum (c), according to the equation n = v/c.

Determine the index of refraction?

The index of refraction (n) is defined as the ratio of the speed of light in vacuum (c) to the speed of light in a medium (v). Mathematically, n = v/c.

In this case, the question states that the light beam has speed c in vacuum and speed v in a certain plastic. Since the index of refraction is defined as the ratio of these two speeds, the answer is n = v/c.

This equation is consistent with the definition and behavior of the index of refraction. When light enters a medium with a higher index of refraction, its speed decreases.

Therefore, the index of refraction (n) must be greater than 1. In the given options, option C (n = v/c) satisfies this condition, whereas the other options do not.

To know more about refraction, refer here:

https://brainly.com/question/13088981#

#SPJ4

a toaster draws a current of 9.0 a when it is connected to a 110-v ac line. a. what is the power consumption of this toaster? b. what is the resistance of the heating element in the toaster?

Answers

The answers are :

a. The power consumption of the toaster is 990 W (watts).

b. The resistance of the heating element in the toaster is approximately 12.2 Ω (ohms).

a. Power consumption can be calculated using the formula: Power (P) = Current (I) × Voltage (V).

Current (I) = 9.0 A

Voltage (V) = 110 V

Using the formula, we can calculate the power consumption of the toaster:

P = 9.0 A × 110 V = 990 W

Therefore, the power consumption of the toaster is 990 watts.

b. To calculate the resistance (R) of the heating element in the toaster, we can use Ohm's Law: Resistance (R) = Voltage (V) / Current (I).

Voltage (V) = 110 V

Current (I) = 9.0 A

Using the formula, we can calculate the resistance:

R = 110 V / 9.0 A ≈ 12.2 Ω

Therefore, the resistance of the heating element in the toaster is approximately 12.2 ohms.

a. The toaster consumes 990 watts of power when connected to a 110 V AC line.

b. The resistance of the heating element in the toaster is approximately 12.2 ohms. These values are obtained using the formulas for power consumption and resistance, with the given current and voltage values.

To know more about resistance visit:

https://brainly.com/question/24182272

#SPJ11

Light is incident along the normal on face AB of a glass prism of refractive index 1.52, as shown in the figure (Figure 1). Find the largest value the angle alpha can have without any light refracted out of the prism at face AC If the prism Is immersed in air. Find the largest value the angle alpha can have without any light refracted out of the prism at face AC if the prism is immersed in water.

Answers

The largest value the angle alpha can have without any light refracted out of the prism at face AC, when the prism is immersed in air, is 41.8 degrees. When the prism is immersed in water, the largest value the angle alpha can have without any light refracted out of the prism at face AC is 24.7 degrees.

The critical angle can be calculated using Snell's law and the definition of the critical angle. The critical angle (θc) is the angle of incidence at which the refracted angle (θr) is 90 degrees.

For the prism immersed in air:

The refractive index of air (n1) is approximately 1.00. The refractive index of the prism (n2) is 1.52.

Using Snell's law:

n1 * sin(θ1) = n2 * sin(θ2)

1.00 * sin(90 degrees) = 1.52 * sin(θc)

1 = 1.52 * sin(θc)

sin(θc) = 1 / 1.52

θc = arcsin(1 / 1.52)

θc ≈ 41.8 degrees

For the prism immersed in water:

The refractive index of water (n1) is approximately 1.33.

Using Snell's law:

n1 * sin(θ1) = n2 * sin(θ2)

1.33 * sin(90 degrees) = 1.52 * sin(θc)

1 = 1.52 * sin(θc)

sin(θc) = 1 / 1.52

θc = arcsin(1 / 1.52)

θc ≈ 24.7 degrees

The largest value the angle alpha can have without any light refracted out of the prism at face AC is approximately 41.8 degrees when the prism is immersed in air, and approximately 24.7 degrees when the prism is immersed in water. These values represent the critical angles at which total internal reflection occurs, preventing light from refracting out of the prism.

To know more about prism , visit

https://brainly.com/question/3891897

#SPJ11

You are observing a star about 95 trillion km (10 lightyears) away. How old is the most recent information you can get about this star?
A) 100 years
B) 300,000 seconds
C) This can't be determined without having more information.
D) 95 trillion seconds
E) 10 years

Answers

The most recent information that can be obtained about this star is 100 years old as it takes 10 years for the light from that star to reach Earth

The star that you're observing is about 10 lightyears away. One light year is defined as the distance traveled by light in one year. The speed of light is approximately 300,000 km/s, and there are approximately 31.536 million seconds in one year.

Therefore, we can calculate the distance of 10 lightyears as follows:10 lightyears = (10 * 31.536 million seconds) * (300,000 km/s)= 9.461 * 10¹⁵ km.

So, it's evident that we are observing the star from a very distant place. Light takes time to travel, and the farther we are from the star, the older the information will be. Therefore, the answer to the question is A) 100 years. The most recent information that can be obtained about this star is 100 years old as it takes 10 years for the light from that star to reach Earth, and since we are 10 lightyears away from the star, the information we receive about that star is 10 years old, which means that we can only observe the star as it was 10 years ago.

learn more about distance Refer: https://brainly.com/question/22599939

#SPJ11

A charge of 12 C passes through an electroplating apparatus in 2.0 min. What is the average current?
A) 1.0 A B) 0.60 A C) 0.24 A D) 0.10 A E) 6.0

Answers

The average current passing through the electroplating apparatus is 0.10 A. To calculate the average current, we need to use the formula: Average Current = Total Charge / Total Time

Given that the charge passing through the apparatus is 12 C and the time is 2.0 min, we can substitute these values into the formula:

Average Current = 12 C / 2.0 min

However, it is important to note that the unit of time should be converted to seconds before performing the calculation. There are 60 seconds in a minute, so 2.0 min is equal to 2.0 min x 60 s/min = 120 s.

Now we can calculate the average current:

Average Current = 12 C / 120 s = 0.10 A

Therefore, the average current passing through the electroplating apparatus is 0.10 A.

Learn more about electroplating apparatus here:

https://brainly.com/question/31792549

#SPJ11.

Touch may communicate many different meanings including
a. all of the above. b. control. c. positive emotions
d. playfulness.

Answers

Touch can communicate various meanings, including control, positive emotions, and playfulness, among others. Option A is the correct answer.

A touch is a powerful form of nonverbal communication that can convey a wide range of meanings and emotions. It has the ability to communicate control, such as a firm handshake or a guiding touch. Touch can also express positive emotions, such as affection, comfort, or support, through gentle caresses or hugs.

Additionally, touch can convey playfulness, as seen in playful nudges or tickling. The act of touch is versatile and can encompass all of these meanings and more, making it an essential and nuanced form of human interaction and expression. Therefore, option a. "all of the above" is the correct answer.

Learn more about ways of communication at

https://brainly.com/question/26532034

#SPJ4

A 32 lb weight is attached to a spring suspended from a ceiling. The weight stretches the spring 2 ft. The weight is then pulled down 6 in. below its equilibrium position and released at T = No external forces are present: but resistance of the medium is 10ds (Ft. per sec.) Find the equation of the motion.

Answers

This is the equation of motion for the weight attached to the spring

32 * y'' = -k * 2 + 32 * 32 - 10 * y'

Let's denote the equilibrium position of the weight as the reference point (y = 0). When the weight is pulled down 6 inches below equilibrium, its displacement is -0.5 ft. We can choose the downward direction as positive.

1. Determine the spring force:

The spring force is proportional to the displacement from the equilibrium position and follows Hooke's Law: F_spring = -k * y, where k is the spring constant. Since the weight stretches the spring by 2 ft, we have F_spring = -k * 2 ft.

2. Determine the force due to gravity:

The weight has a mass of 32 lb, so the force due to gravity is F_gravity = m * g, where g is the acceleration due to gravity (32 ft/s^2).

3. Determine the force due to resistance:

The force due to resistance is given as F_resistance = -10 * y' ft/s, where y' is the velocity of the weight.

Applying Newton's second law, the sum of the forces equals the mass of the weight times its acceleration:

m * y'' = F_spring + F_gravity + F_resistance

32 lb * y'' = -k * 2 ft + 32 lb * 32 ft/s^2 - 10 ft/s * y'

Simplifying the equation and converting the mass and force units to the appropriate unit system, we have:

32 * y'' = -k * 2 + 32 * 32 - 10 * y'

This is the equation of motion for the weight attached to the spring. The specific value of k and any initial conditions would be needed to solve the equation further and obtain a more detailed motion equation.

for more questions on motion
https://brainly.com/question/26083484
#SPJ8

You will begin with a relatively standard calculation. Consider a concave spherical mirror with a radius of curvature equal to 60.0 centimeters. An object 6.00 centimeters tall is placed along the axis of the mirror, 45.0 centimeters from the mirror. You are to find the location and height of the image.
What is the focal length fff of this mirror?
Now use the spherical mirror equation to find the image distance s′
Find the magnification mmm, using sss and s′
Finally, use the magnification to find the height of the image y′y′y'.
Look at the signs of your answers to determine which of the following describes the image formed by this mirror:
a. real and upright
b. real and inverted
c. virtual and upright
d. virtual and inverted

Answers

The focal length of the concave spherical mirror is -30.0 cm. The image is formed at a distance of -60.0 cm from the mirror. The magnification is -0.5, and the height of the image is -3.00 cm.

Given:

Radius of curvature (R) = 60.0 cm

Object height (y) = 6.00 cm

Object distance (s) = 45.0 cm

To find the focal length (f) of the mirror, we use the mirror formula:

1/f = 1/s + 1/s'

Since the object is placed outside the focal length, the mirror is a concave mirror, and the focal length will be negative:

1/f = 1/s - 1/s'

Substituting the values:

1/f = 1/45.0 cm - 1/s'

To find the image distance (s'), we rearrange the equation:

1/s' = 1/f - 1/s

Substituting the values:

1/s' = 1/(-30.0 cm) - 1/45.0 cm

1/s' = -0.0333 cm^(-1)

s' = -30.0 cm

The negative sign indicates that the image is formed on the same side as the object, making it a real image.

The magnification (m) is given by:

m = -s'/s

Substituting the values:

m = -(-30.0 cm) / 45.0 cm

m = -0.6667

The negative sign indicates that the image is inverted.

The height of the image (y') is given by:

y' = m * y

Substituting the values:

y' = -0.6667 * 6.00 cm

y' = -4.00 cm

The negative sign indicates that the image is inverted.

The focal length of the concave spherical mirror is -30.0 cm. The image is formed at a distance of -60.0 cm from the mirror. The magnification is -0.5, and the height of the image is -3.00 cm. Based on the signs of the answers, the image formed by this mirror is real and inverted.

To know more about Concave spherical mirror visit:

https://brainly.com/question/31951940

#SPJ11

Which of the following best describes the image from a plane mirror? a)virtual and magnification greater than one b)real and magnification less than one c)virtual and magnification equal to one d)real and magnification equal to one *Please explain why*

Answers

The image from a plane mirror is c) virtual and magnification equal to one.

What is plane mirror?

A plane mirror is a flat, smooth mirror with a reflective surface that reflects light in a regular manner. It is called a "plane" mirror because its surface is flat and does not have any curvature.

In a plane mirror, the image formed is virtual, meaning that it is formed by the apparent extension of reflected light rays. It cannot be projected onto a screen and is not formed by the convergence or divergence of actual light rays. The image formed in a plane mirror is also characterized by having a magnification of one. Magnification refers to the ratio of the height of the image to the height of the object. In the case of a plane mirror, the image appears to be the same size as the object, so the magnification is equal to one.

Therefore, the correct description of the image from a plane mirror is virtual and magnification equal to one which is option c.

To learn more about plane mirror,

https://brainly.com/question/14864466

#SPJ4

if an electric field experiences an acceleration from the west what direction is it

Answers

If an electric field experiences an acceleration from the west, the direction of the electric field itself will depend on various factors and cannot be determined solely from the information provided.

The acceleration experienced by an electric field does not provide enough information about the initial direction or configuration of the field.

An electric field is a vector quantity that represents the force experienced by a positive test charge placed in the field. It is typically defined as the force per unit positive charge. However, an electric field can exist independently of any test charge, and its behavior is influenced by the distribution of charges in the vicinity.

The direction of the electric field is determined by the distribution of charges and the configuration of the system. The acceleration experienced by the electric field could be a result of various factors such as the movement of charges, changes in the electric field's source, or the influence of external forces. These factors can influence the direction of the electric field in complex ways.

Therefore, without additional information about the specific configuration and circumstances of the electric field, it is not possible to determine its direction solely based on the given information of experiencing an acceleration from the west. Further details about the system, such as the distribution of charges or the presence of external forces, would be required to determine the direction of the electric field.

To learn more about electric field visit:

brainly.com/question/15800304

#SPJ11

A silicon crystal having a cross-sectional area of 0.001 cm² and a length of 10-3 cm is connected at its ends to a 10-V battery. At T = 300 K, we want a current of 100 mA in the silicon. Calculate (a) the required resistance R, (b) the required conductivity. (c) the density of donor atoms to be added to achieve this conductivity, and (d) the concentration of acceptor atoms to be added to form a compensated p-type material with the conductivity given from part (b) if the initial concentration of donor atoms is Na = 1015 cm-3

Answers

(a) The required resistance R is 100 Ω.

(b) The required conductivity is 10 S/cm.

(c) The density of donor atoms to be added to achieve this conductivity is approximately 10¹⁹ cm⁻³.

(d) The concentration of acceptor atoms to be added to form a compensated p-type material with the desired conductivity is approximately 10¹³ cm⁻³.

Determine find the required resistance?

(a) The required resistance R can be calculated using Ohm's law: R = V/I, where V is the voltage (10 V) and I is the desired current (100 mA = 0.1 A).

Therefore, R = 10 V / 0.1 A = 100 Ω.

Determine find the required conductivity?

(b) The required conductivity can be calculated using the equation: σ = I/(A × L), where σ is the conductivity, I is the current (0.1 A),

A is the cross-sectional area (0.001 cm² = 0.0001 cm²), and L is the length (10⁻³ cm).

Therefore, σ = 0.1 A / (0.0001 cm² × 10⁻³ cm) = 10 S/cm.

Determine find the density of donor atoms?

(c) The density of donor atoms can be calculated using the equation: n = σ/(q × μn), where n is the density of donor atoms, σ is the conductivity (10 S/cm), q is the elementary charge (1.6 × 10⁻¹⁹ C), and μn is the mobility of electrons in silicon (around 1350 cm²/V·s).

Therefore, n ≈ 10 S/cm / (1.6 × 10⁻¹⁹ C × 1350 cm²/V·s) ≈ 10¹⁹ cm⁻³.

Determine find the initial concentration of donor atom?

(d) To form a compensated p-type material, the concentration of acceptor atoms should be equal to the concentration of donor atoms.

Therefore, the concentration of acceptor atoms needed is Na = 10¹⁵ cm⁻³.

To know more about conductivity, refer here:

https://brainly.com/question/21496559#

#SPJ4

A student wants to determine the coefficient of static friction between a long, flat wood board and a
small wood block.
(a) Describe an experiment for determining the coefficient of static friction between the wood board
and the wood block. Assume equipment usually found in a school physics laboratory is available.
i. Draw a diagram of the experimental setup of the board and block. In your diagram,
indicate each quantity that would be measured and draw or state what equipment would
be used to measure each quantity.
ii. Describe the overall procedure to be used, including any steps necessary to reduce
experimental u

Answers

The experiment involves measuring the coefficient of static friction between a wood board and a wood block using a spring balance. The procedure includes cleaning surfaces, tilting the board, and calculating the friction coefficient.

The experiment for determining the coefficient of static friction between the wood board and the wood block is given below:

Clean the surface of the wood board and the wood block.Keep the wood board flat and place the wood block on the board slowly.Start to tilt the board slowly until the block just starts to slide.Measure the angle of inclination [tex]$\theta$[/tex] with the horizontal.Repeat the above step and average the results to obtain more accuracy.Note the weight of the block, [tex]$W$[/tex], with a spring balance, the weight of the board, [tex]$W_2$[/tex], with the spring balance, and the force, [tex]$F$[/tex], required to just move the block when it is on the point of slipping.Draw a free-body diagram of the forces acting on the block.Use the free-body diagram to calculate the coefficient of static friction [tex]$\mu$[/tex] between the block and the board. It is given by [tex]$\mu = \frac{F}{W}$[/tex].

Learn more about static friction: brainly.com/question/13680415

#SPJ11

A mixture of red light (λvacuum =640 nm) and green light (λvacuum =512 nm) shines perpendicularly on a soap film ( n =1.23 ) that has air on both side. What is the minimum nonzero thickness of the film, so that destructive interference causes it to look red in reflected light? nm

Answers

The minimum nonzero thickness of the film for destructive interference to cause it to look red in reflected light is approximately 130.08 nm.

To determine the minimum nonzero thickness of the soap film for destructive interference to cause it to look red in reflected light, we can use the equation for the path length difference

ΔL = 2nt

Where ΔL is the path length difference, n is the refractive index of the soap film, and t is the thickness of the film.

In this case, we want destructive interference to occur for the red light component (640 nm), which means the path length difference should be equal to half of its wavelength.

ΔL = λred/2

Substituting the given values

ΔL = (640 nm)/2 = 320 nm

Now, we can rearrange the equation to solve for the thickness of the film (t)

t = ΔL / (2n)

t = (320 nm) / (2 * 1.23)

t = 130.08 nm

Therefore, the minimum nonzero thickness of the film for destructive interference to cause it to look red in reflected light is approximately 130.08 nm.

To know more about destructive interference here

https://brainly.com/question/31381708

#SPJ4

how does the actual momentum of the bus compare with the momentum it would have if classical mechanics were valid?

Answers

The actual momentum of the bus compare with the momentum it would have if classical mechanics were valid due to the fundamental differences between quantum mechanics and classical mechanics.

According to quantum mechanics, particles can exhibit wave-like behavior. When particles have wavelengths that are comparable to the size of objects, they are said to be delocalized, this means that an object can have a wave function that is spread out over a large region of space. This leads to uncertainty in the object's position and momentum. Therefore, in the macroscopic world, we do not observe quantum effects and classical mechanics work very well. On the other hand, classical mechanics deals with objects that are much larger than atoms and particles.

In classical mechanics, the momentum of an object is given by the product of its mass and velocity, it does not depend on the object's wave-like properties. However, in the world of quantum mechanics, the concept of momentum is not as straightforward as it is in classical mechanics. An object's momentum in quantum mechanics is represented by its wave function, which is a complex function that describes the probability of finding the object in a particular state or location.

So, the actual momentum of the bus may not be directly comparable with the momentum it would have if classical mechanics were valid. In conclusion, the actual momentum of the bus may not be directly comparable with the momentum it would have if classical mechanics were valid due to the fundamental differences between quantum mechanics and classical mechanics.

To know more about quantum mechanics visit:

https://brainly.com/question/23780112

#SPJ11

A charge of -2.50nC is placed at the origin of an xy-coordinate system, and a charge of 2.05nC is placed on the y axis at y = 3.80cm . If a third charge of 5.00nC, is placed at the point x=3.10cm, y=3.80cm find the x and y components of the total force exerted on the charge by two other charges.

Answers

To find the x and y components of the total force exerted on the third charge by the other two charges, we can use Coulomb's law to calculate the forces individually and then add their vector components.

Let's denote the charges as follows: Charge at the origin (Q1) = -2.50 nC Charge on the y-axis (Q2) = 2.05 nC Charge at point (x=3.10 cm, y=3.80 cm) (Q3) = 5.00 nC. Coulomb's law states that the force between two charges is given by: F = (k * |Q1 * Q2|) / r^2, Where: F is the force between the charges. k is the electrostatic constant (k = 8.99 x 10^9 N m^2/C^2). |Q1 * Q2| is the magnitude of the product of the charges. r is the distance between the charges. First, let's calculate the force between Q1 and Q3: Distance between Q1 and Q3: r1 = sqrt((x3 - x1)^2 + (y3 - y1)^2). r1 = sqrt((3.10 cm - 0 cm)^2 + (3.80 cm - 0 cm)^2). Magnitude of the product of charges: |Q1 * Q3| = |(-2.50 nC) * (5.00 nC)|. Now we can calculate the x and y components of the force between Q1 and Q3 using the following equations:

F1x = (k * |Q1 * Q3| * (x3 - x1)) / r1^3

F1y = (k * |Q1 * Q3| * (y3 - y1)) / r1^3

Next, let's calculate the force between Q2 and Q3: Distance between Q2 and Q3: r2 = sqrt((x3 - 0 cm)^2 + (y3 - 3.80 cm)^2). Magnitude of the product of charges: |Q2 * Q3| = |(2.05 nC) * (5.00 nC)|. Now we can calculate the x and y components of the force between Q2 and Q3 using the following equations:

F2x = (k * |Q2 * Q3| * x3) / r2^3

F2y = (k * |Q2 * Q3| * (y3 - 3.80 cm)) / r2^3

Finally, we can find the total x and y components of the force by summing the individual components:

Total Fx = F1x + F2x

Total Fy = F1y + F2y

Substitute the given values into the equations and perform the calculations to find the x and y components of the total force exerted on the charge by the other two charges.

To learn more about charge, https://brainly.com/question/13871705

#SPJ11

If an animal's heart beats two times each second, what is the period?
a) 2.0 s. b) 4.0 s. c) 0.25 s. d) 0.50 s

Answers

If an animal's heart beats two times each second, the time period is of 0.50 s.

What is time period?

Time period refers to the duration or time it takes for one complete cycle or oscillation of a repetitive motion to occur. It is the time interval between two consecutive identical points or events in the motion.

The frequency is given as 2 beats per second, which means that in one second, there are 2 cycles. Therefore, the period is the inverse of the frequency:

Period = 1 / Frequency

Plugging in the given frequency:

Period = 1 / 2 Hz

Simplifying the expression, we find:

Period = 0.5 seconds

Therefore, If an animal's heart beats two times each second, the time period is of 0.50 s which is option d.

To learn more about time period,

https://brainly.com/question/14476485

#SPJ4

A parallel-plate capacitor is charged by a 18.0Vbattery, then the battery is removed.

What is the potential difference between the plates after the battery is disconnected?

hat is the potential difference between the plates after a sheet of Teflon is inserted between them?

Express your answer with the appropriate units.

Answers

The potential difference between the plates after the battery is disconnected would still be 18.0V.

The potential difference between the plates would still be 18.0V

How to determine the  potential difference

When a parallel-plate capacitor is charged by a battery and then the battery is removed, the potential difference between the plates remains the same. Therefore, the potential difference between the plates after the battery is disconnected would still be 18.0V.

Now, if a sheet of Teflon is inserted between the plates, the dielectric constant of Teflon would affect the capacitance of the capacitor, but not the potential difference between the plates.

The potential difference between the plates would still be 18.0V even with the Teflon sheet inserted between them. The Teflon would only alter the capacitance and the amount of charge stored on the plates, but the potential difference remains unchanged.

Read m ore on potential difference here https://brainly.com/question/24142403

#SPJ4

An Atwood's machine consists of two masses, mA and mB, which are connected by a massless inelastic cord that passes over a pulley, see the figure(Figure 1) .
Part A
If the pulley has radius R and moment of inertia I about its axle, determine the acceleration of the masses mA and mB. [Hint: The tensions FTA and FTBare not equal. We discussed the Atwood machine in Example 4-13 in the textbook, assuming I=0 for the pulley.]

Answers

The acceleration of the masses mA and mB in terms of the variables mA, mB, I, and the appropriate constants is a = (mA - mB) * R² / I

To determine the acceleration of the masses mA and mB in an Atwood's machine with a pulley of radius R and moment of inertia I about its axle, we need to consider the forces acting on the masses.

Let's assume that mass mA is greater than mass mB (mA > mB). The forces acting on mA are its weight (mg) downward and the tension in the cord (FTA) upward. The forces acting on mB are its weight (mg) downward and the tension in the cord (FTB) upward.

Using Newton's second law (F = ma) for each mass, we can set up the following equations:

For mA:

mg - FTA = mA * a (equation 1)

For mB:

mg - FTB = mB * a (equation 2)

Next, we need to consider the torque (τ) exerted on the pulley due to the net force (FTB - FTA). The torque is given by τ = Iα, where α is the angular acceleration of the pulley.

Since the cord is assumed to be inelastic, the linear acceleration (a) of both masses is equal to the linear acceleration of the pulley, and the angular acceleration (α) of the pulley is related to the linear acceleration by α = a / R.

Now, let's express the tension in terms of the linear acceleration of the pulley and solve for the tensions:

FTA = mB * g - mB * a (from equation 2)

FTB = mA * g - mA * a (from equation 1)

Substituting these values into the torque equation, we have:

(I / R²) * (a / R) = (mA * g - mA * a) - (mB * g - mB * a)

Simplifying the equation, we get:

(I / R²) * (a / R) = (mA - mB) * a

Now, we can solve for the linear acceleration (a). Multiplying through by (R³ / (mA - mB)), we obtain:

(I / R²) * a = (mA - mB) * a * R²

Canceling out 'a' from both sides of the equation, we have:

I = (mA - mB) * R²

Finally, the linear acceleration (a) can be expressed as:

a = (mA - mB) * R² / I

For more such questions on acceleration,click on

https://brainly.com/question/460763

#SPJ8

Other Questions
15. According to the text, the two main issues for management to consider in designing an international company's structure include which of the following?A. Departmentalizing to most effectively take advantage of efficiencies gained from specialization of capital.B. Integrating functions to achieve lowest possible costs.C. Ensuring that policies and procedures can enable continued product innovation.D. Coordinating departments' activities to meet the firm's overall objectives.E. Ensuring that power is dispersed so that dependency on individual units is minimized. Describe a situation that can be represented by the integer - 6 Listen and choose the option with the best answer to the question.Based on the audio, select the statement that seems most true.Angelica and her aunt do the grocery shopping on weekends.O Angelica and her aunt go to the beach on weekends.Angelica and her aunt visit with friends on the weekends.O Angelica and her aunt see a movie on weekends. Explain the difference between linear, exponential, and quadratic functions in terms of their graphs, their patterns, and their rates of change. I can't figure this problem out- Please help me Write the net cell equation for this electrochemical cell. Phases are optional. Do not include the concentrations.Co(s)Co2+(aq, 0.0155 M)Ag+(aq, 2.50 M)Ag(s) Identify a true statement about the bring your own device (BYOD) business policy.a. It can improve employee productivity.b. It can provide data security.c. It creates a bug-free environment.d. It enhances employee interaction. PLEASE HELP !!!! ILL GIVE BRAINLIEST !!! the functions y=x^2+ (c/x^2) are all solutions of equation: xy 2y=4x^2, (x>0). find the constant c which produces a solution which also satisfies the initial condition y(6)=4. c= ______-- Which of the following was an activity of the NAACP?a Supporting environmental issues in Texas' natural habitatsb. Organizing and financing lawsuits to stop segregationC. Supporting marksmanship and gun safety in Texasd. Organizing and supporting stronger drunk driving lawsPlease select the best answer from the choices providedAB Dani has only 1/2 of a cup of baking mix. She needs 3/4 of a cup for one batch of muffins. Which solution method shows how much of a batch of muffins Dani can make? Help!!!!Escribe la forma plural de las siguientes palabras. Solve the system using substitution. Show all work.( 4 + 5y = 7 = 3 + 9 HELP PLEASEEEE IT WOULD HELP ME OUT A LOT Should children have to work for an allowance or should it just be given to them?Why or why not? (introduction) "6 less than the quotient of a number and 5" An unknown acid, HA, has a percent dissociation of 2.16%. If the initial concentration of the acid is 0.084 M. what is the pH of the solution? A.1.08 B.11.26 C.2.74 D.1233 E.1.67 28)What is a molecule made from joining together small molecules called monomers?A)amino acidB)glucose moleculenucleotideD)polymer derive the error propagation equation for k (the kinetic energy). is sublimation a chemical change or chemical property or physical change?