Iodine-131 has a half-life of 8 days. How many grams of a 256 g sample would remain at the end of 56 days?

Answer:

79.3

Explanation:

We can use the formula:

q = m * c * deltaT

where:

q is the heat added to the system, which is 815 J in this case

m is the mass of the sample we want to find

c is the specific heat of copper, which is 0.385 J/g-K

deltaT is the change in temperature, which is (35 - 12) = 23°C

Plugging in the values given, we get:

815 J = m * 0.385 J/g-K * 23°C

Simplifying this expression yields:

m = 815 J / (0.385 J/g-K * 23°C)

Thus, the mass of the copper sample is:

m = 79.3 g

Therefore, there were approximately 79.3 grams of copper in the sample.

Answer:

Explanation:

We can use the equation q = mCΔT, where q is the amount of heat transferred, m is the mass of the sample, C is the specific heat capacity of the material, and ΔT is the change in temperature.

First, we need to calculate the change in temperature, which is:

ΔT = T₂ - T₁ = 35°C - 12.0°C = 23°C

Next, we can rearrange the equation to solve for the mass of the sample:
m = q / (CΔT)

Substituting the values we have:
m = 815 J / (0.385 J/g-K × 23°C) ≈ 90.2 g

Therefore, the sample of solid copper had a mass of approximately 90.2 grams.

The velocity reached by the soccer player is 2.7 m/s.

Impulse applied by the soccer player = 200 Ns

Mass of the soccer player = 74 kg

According to impulse-momentum theorem, the average net external force multiplied by the time it takes for that force to take effect equals the impulse, which is equal to the change in momentum.

Impulse = Fnet × t

Fnet x t = ma × t = m × v

mv = ΔP

where ΔP is the change in momentum.

So,

The change in momentum of the player, ΔP = 200 Kgm/s

So, velocity reached, v = 200/74

v = 2.7 m/s

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Answer:

Both Corks are subject to the same buoyant force

Explanation:

The buoyant force depends on the volume of the displaced liquid and the density of the liquid, but not the density of the floating object. So the buoyant forces will be the same on each cork whether the water it's floating in is normal or salty.

The highlighted phenomenon in the graph is called the Doppler effect, which involves a modification of frequency for sound waves (or any kind of wave) due to the difference in motion between the observed and the source.

An example of this effect present in the medical field is through ultrasound imaging; doctors use it to measure the velocity and route of blood circulating throughout the patient's body by sending out high-frequency sound waves and analyzing the reflected waves.

What appears in the graphed illustration specifically is linear proportionality, meaning that there is a direct correlation between f and fs, the former being the observed frequency and the latter the source frequency.

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Answer:

False

Explanation:

The modern kinetic-molecular model is better than the caloric model, not because it is true, but because it produces more workable results. credited to be the first to demonstrate a clear connection between mechanical energy and heat.

Neither MacBook Air nor the direction that the sound waves travel affects the speed of the sound.

If you do 12 J of work to push 0.001 C of charge from point A to point B in an electric field, then the potential difference between points A and B is 12 kV.

The increase in kinetic energy of an electron if it has been accelerated through a potential difference of 20 million volts is 8000 J.

a )When a charge is accelerated through potential difference then the energy gained by the charge is,

E = eV where E is energy e is charge and V is potential difference.

V = E/e = 12/0.001 = 12 kV

b) E = eV, E = 0.001 × 20×10⁶

E = 20000 J

Increase in the kinetic energy will be, 20000 - 12000 = 8000 J

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Answer:

7.00 KJ

Explanation:

GPE = mgh

m equals mass (kg)

g is a constant which equals 9.81 m/s

h equals height (m)

GPE = (25.8 kg)(9.81 m/s)(27.66 m)

GPE = 7,000.69 J or 7.00 KJ

the force F required for equilibrium is 128.397 N.

There are two main forces: the weight of the cylinder A and the hydraulic pressure acting on the piston B. The weight of A is given by:

W = m*g = 13 kg * 9.81 m/s^2 = 127.53 N

P = rho x gx h

where

h = (15000 mm^2) / (2 m^2) = 0.0075 m

pressure is:

P = 780 kg/m^3 * 9.81 m/s^2 * 0.0075 m = 57.79 N/m^2

Force = P*A

A = 15000 mm^2 = 0.015 m^2

Force = 57.79 N/m^2 * 0.015 m^2 = 0.867 N

Solving  for the force required for equilibrium:

Force = W + P*A

Force = 127.53 N + 57.79 N/m^2 * 0.015 m^2

= 127.53 N + 0.867 N

= 128.397 N

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Answer:

The approximate temperature required to begin fusion in a star is C. 14 million kelvins. This temperature is high enough to overcome the electrostatic repulsion between positively charged atomic nuclei, allowing them to fuse and form heavier elements.

A scientific research consists of numerous critical phases. Here's a high-level summary of the procedure: Create a research question, then conduct a review of the literature. Create a hypothesis. Create your research, Gather information, Examine data, Interpret findings and communicate them.

Create a research question: Begin by picking a topic of interest and creating a clear and precise question that you wish to answer via your research.

Conduct a literature review : before beginning your study to establish what is already known about your issue and what research questions have not yet been answered.

Create a hypothesis: Based on your research topic and analysis of the literature, create a hypothesis that you can evaluate using your study

Plan your research as follows: Determine your data collecting and analysis approach, including the research design, population/sample, data gathering methods, and statistical analysis.

Gather information: Carry out your research and gather data in accordance with your approach.

Analyse data: Once you've gathered your information, use relevant statistical tools to test your hypothesis.

Results should be interpreted as follows: Interpret your findings and develop conclusions about your research issue based on your analysis.

Disseminate findings: Share your discoveries with others by publishing them in a scientific journal, giving a presentation at a conference, or another method.

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The projectile with the smallest angle of elevation will have the greatest kinetic energy just before impact.

All three projectiles have the same initial kinetic energy, which means that they all start with the same amount of energy. However, the kinetic energy of a projectile is related to its velocity and mass.

When a projectile is launched at an angle of elevation, its initial velocity will have both horizontal and vertical components. The vertical component of velocity will affect the time it takes for the projectile to reach the ground, but it does not affect the kinetic energy of the projectile just before impact.

Therefore, the projectile with the greatest kinetic energy just as it impacts with the ground will be the one with the largest horizontal component of velocity, which means it will travel the furthest horizontally before hitting the ground.

The horizontal component of velocity is determined by the angle of elevation and the initial velocity of the projectile. Therefore, the projectile with the smallest angle of elevation will have the largest horizontal component of velocity and therefore the greatest kinetic energy just before impact.

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The false statement regarding gender roles is, they stem primarily from biological differences in the sexes. Option b is correct.

Gender roles are based on cultural traditions and societal norms, rather than solely being determined by biological differences between males and females. While biological differences between the sexes may play a role in certain gender-based behaviors or expectations, the vast majority of gender roles are socially constructed and learned through cultural traditions and socialization. Option b is correct.

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Answer:

Moment of the force = (-10i-28j+32k)Nm

Explanation:

Moment of a force is expressed mathematically as force(F) multipled by its distance(d) and its unit is in newton metre (Nm).

F×d

(8i-4j+3k)×[(6i+2j+3k)-(2i+0j+k)]

-10i-28j+32k

Answer:

Water and hydrogen peroxide are different substances because they have different chemical formulas and molecular structures. Water has the chemical formula H2O, meaning that it has two hydrogen atoms and one oxygen atom. Hydrogen peroxide has the chemical formula H2O2, meaning that it has two hydrogen atoms and two oxygen atoms. The difference in their molecular structures leads to different chemical and physical properties, such as boiling points, melting points, and reactivity.

Explanation:

Mass of the second object located at a distance r from the origin, r^ is the unit vector in the radial direction, and the negative sign indicates that the force

The System can refer to a set of interacting or interdependent components forming an integrated whole. The term can be applied to various fields, including physics, engineering, biology, and social sciences, among others. In physics, a system typically refers to a collection of objects or particles that are studied together, often with the goal of understanding the behavior of the system as a whole. In engineering, a system can refer to a group of components that work together to perform a specific function, such as an electrical power grid or an automobile engine. In biology, a system can refer to an organism or group of organisms that interact with their environment, such as an ecosystem or the human body.

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Answer:

KE = 100J and PE = 100J

Explanation:

[tex]KE = 0.5*m*v^2\\PE = m*g*h\\KE = 0.5*2*100 = 100 J[/tex]

Potential energy at the start has to equal the kinetic energy at the end due to conservation of energy

The refracted angle of the electromagnetic wave in glass (θ₂) is approximately 59.64° when the incident angle (θ₁) is 25°.

The refracted angle, denoted as θ₂, can be calculated using Snell's Law, which relates the incident angle, refracted angle, and the refractive indices of the two media involved.

Snell's Law states:

n₁ × sin(θ₁) = n₂ × sin(θ₂)

where:

n₁ = refractive index of the first medium (water) = 1.3

θ₁ = incident angle of the wave in the first medium = 25°

n₂ = refractive index of the second medium (glass) = 1.5

θ₂ = refracted angle of the wave in the second medium

Plugging in the given values:

n₁ = 1.3

θ₁ = 25°

n₂ = 1.5

Can rearrange Snell's Law to solve for θ₂:

θ₂ = arcsin((n₁/n₂) × sin(θ₁))

Now we can substitute in the values and calculate θ₂:

θ₂ = arcsin((1.3/1.5) × sin(25°))

θ₂ = arcsin(0.8667)

θ₂ ≈ 59.64°

So the refracted angle of the electromagnetic wave in glass (θ₂) is approximately 59.64° when the incident angle (θ₁) is 25°.

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The question is incomplete. Here is how to get magnitude and direction

To find the magnitude and direction of a vector, follow these steps:

Write the vector in component form:

For a two-dimensional vector, write it as <x, y>, where x and y are the components of the vector along the x-axis and y-axis, respectively. For a three-dimensional vector, write it as <x, y, z>, where x, y, and z are the components of the vector along the x-axis, y-axis, and z-axis, respectively.

Calculate the magnitude of the vector:

The magnitude of a vector is the length of the vector, which can be found using the Pythagorean theorem. For a two-dimensional vector <x, y>, the magnitude is sqrt(x^2 + y^2). For a three-dimensional vector <x, y, z>, the magnitude is sqrt(x^2 + y^2 + z^2).

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Answer:

17.3 m/s

Explanation:

We can use the conservation of energy principle to find the velocity of the log when it hits the water. At the top of the waterfall, the log has gravitational potential energy, and at the bottom, it has kinetic energy. We can assume that there is no energy lost to friction or air resistance.

The gravitational potential energy of the log at the top of the waterfall is given by:

U = mgh

where m is the mass of the log, g is the acceleration due to gravity, and h is the height of the waterfall. Substituting the given values, we get:

U = (15.0 kg)(9.81 m/s^2)(30 m) = 4414.5 J

At the bottom of the waterfall, all of the gravitational potential energy has been converted to kinetic energy:

U = (1/2)mv^2

where v is the velocity of the log when it hits the water. Solving for v, we get:

v = sqrt(2U/m)

Substituting the value of U and m, we get:

v = sqrt(2(4414.5 J)/(15.0 kg)) = 17.3 m/s

Therefore, the velocity of the log when it hits the water is approximately 17.3 m/s.

Hope this helps!

Answer:

23 ohm

Explanation:

I = I1 = I2 = 0.25A

V = 6 V

V = V1 + V2

6 = I1R1 + I2R2

6 = ( 0.25 × 1 ) + ( 0.25 × R2 )

6 = 0.25 + 0.25 R2

6 - 0.25 = 0.25 R2

5.75 = 0.25 R2

5.75 ÷ 0.25 = R2

R2 = 23 ohm

Explanation:

d = do + vo t + 1/2 at^2

d = 0 +  14.5 (2) + 1/2 (9.80)(2^2) = 48.6 = ~ 49 m

Explanation:

d = do + vo t + 1/2 at^2

d = 0 +  14.5 (2) + 1/2 (9.80)(2^2) = 48.6 = ~ 49 m

The difference, between the higher and lower temperatures in Fahrenheit degrees is 87.8  °F.

​The difference, between the higher and lower temperatures in Fahrenheit degrees is calculated as follows;

The difference in the temperatures = 34 °C  -  3°C = 31 °C

Convert the temperature to Fahrenheit degrees as follows;

31 °C = 1.8C + 32

31 °C = 1.8 x 31  + 32

31 °C = 87.8  °F

Thus, the difference, between the higher and lower temperatures in Fahrenheit degrees is calculated using the conversion factor.

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The tea absorbs 2613420 J of heat energy when it is placed in sunlight until it reaches an equilibrium temperature of 32.4°C.

To calculate the heat energy absorbed by the tea, we can use the formula:

Q = mcΔT

where Q is the heat energy absorbed by the tea, m is the mass of the tea, c is the specific heat capacity of water, and ΔT is the temperature change of the tea.

Using the given values, we get:

m = 500 g

c = 4186 J/kg·°C

ΔT = 32.4°C - 20°C = 12.4°C

Substituting these values into the formula, we get:

Q = (500 g)(4186 J/kg·°C)(12.4°C) = 2613420 J

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--The complete Question is, A jar of tea with a mass of 500 g is initially at a temperature of 20°C. If the jar is placed in sunlight until it reaches an equilibrium temperature of 32.4°C, how much heat energy is absorbed by the tea? Assume the specific heat capacity of the tea to be that of pure liquid water, which is 4186 J/kg·°C.--

Astronomers can use how long it takes an object's brightness to vary to estimate the physical size of the object through a method known as photometry. This method involves observing an object's brightness over time and analyzing the patterns of variation.

For example, consider a binary star system in which two stars orbit each other. As one star passes in front of the other, the combined brightness of the system will decrease. The duration of this decrease in brightness can be used to estimate the physical size of the stars, as the duration of the decrease is related to the size of the stars and the distance between them.

Similarly, if an asteroid or other small body passes in front of a star, the star's brightness will decrease for a short period of time. The duration of this decrease can be used to estimate the size of the asteroid, as the duration is related to the size of the asteroid and the distance between it and the observer.

In general, the size of an object can be estimated using photometry by comparing the observed variation in brightness to the expected variation based on the physical characteristics of the object. This can provide valuable information about the properties and behavior of celestial objects and can help astronomers to better understand the structure and evolution of the universe.

The resistor is dissipating 1.8 W of power. As a result, 0.15 A is the current flowing through the resistor.

Any equation linking power to current, voltage, and resistance may be used to calculate the power wasted by each resistor because all three variables are known. Since each resistor receives its full voltage, let's use P=V2R P = V 2 R.

(a) We may determine the current flowing through the resistor using Ohm's Law as follows:

I = V/R

where R is the resistance and V is the voltage difference across the resistor.

Therefore, the resistor's current is as follows:

I = 12 V / 80 Ω = 0.15 A

Therefore, the current through the resistor is 0.15 A.

(b) The power being dissipated in the resistor can be calculated using the formula:

P = VI = I²R = V²/R

where P is the power, V is the voltage difference across the resistor, I is the current through the resistor, and R is the resistance.

Substituting the given values, we get:

P = VI = (0.15 A)(12 V) = 1.8 W

Alternatively, we can use the third formula to calculate the power:

P = V²/R = (12 V)²/ 80 Ω = 1.8 W

So, the power being dissipated in the resistor is 1.8 W.

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The maximum speed of the cart is 26.07 cm/s, the velocity of the cart when the position is 2 cm is 0.141 m/s, and the kinetic and potential energies of the system are 4.97 ×10⁻³J and 4×10⁻³J.

From the given,

Mass of the cart = 0.5 kg

Force constant = 20 N/m

The amplitude of the motion = 3 cm = 0.03 m

A) maximum speed of the cart=?

ω = √k/m

   = √(20/0.5) = 8.944

v = ω×amplitude = 8.944×3 = 26.07 cm/s.

B) Velocity of the cart when the position is 2 cm

v = √k/m(A²-x²)

  = √(20/0.5)((0.03)²-(0.02)²)

 = 0.141 m/s

C) Kinetic energy = 1/2 (mv²)

                        = 1/2 (0.5×(0.141)²)

                        = 4.97 × 10⁻³J

K.E = 4.97 ×10⁻³J

Potential energy = 1/2 kx²

                            = 1/2 (20×(2×10⁻²)²)

                            = 4 × 10⁻³J

P.E = 4 × 10⁻³J.

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Answer:The oxygen molecules have lost a total of 0.94 coulombs in charge of their electrons.

Explanation:No