The statement that is always true of an object that has kinetic energy is "the object is moving.
Hence, the correct option is B.
Kinetic energy is the energy possessed by an object due to its motion. It is directly related to the object's velocity or speed.
An object must be in motion to have kinetic energy.
When an object is at rest, its kinetic energy is zero because it is not moving. Therefore, option A) "the object is at rest" is not true for an object that has kinetic energy.
Options C) "the object is moving through the air" and D) "the object is suspended above the ground" are not always true for an object with kinetic energy.
An object can have kinetic energy regardless of whether it is moving through the air or suspended above the ground. Kinetic energy depends on the object's motion, not its specific surroundings.
Hence, the statement that is always true of an object that has kinetic energy is B) "the object is moving."
Hence, the correct option is B.
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1. Biodiversity refers to the variety of life in an ecosystem.
False
True
Mention three bodies/organizations that need electricity 24 hours
There are three types of electricity – baseload, dispatchable, and variable
if, while standing on a bank, you wish to spear a fish beneath the water surface in front of you, should you aim above, below, or directly at the observed fish to make a direct hit?
You should aim below the observed fish to make a direct hit. It's essential to practice and gain experience to develop a better understanding of how refraction affects your aim in different situations.
When light passes from one medium (air) to another (water), it undergoes refraction, which causes the light rays to change direction.
This phenomenon is the reason why objects submerged in water appear to be at a different position than they actually are.
To understand how refraction affects spearfishing, we need to consider the path of light rays.
When you look at a fish in the water, the light rays coming from the fish travel through the water and then enter your eyes.
However, when you aim the spear at the fish, the light rays from the fish will follow a different path due to refraction.
The key point is that light rays bend towards the perpendicular when they pass from a less dense medium (air) to a more dense medium (water).
This means that the fish will appear higher in the water than it actually is. To compensate for this apparent displacement, you need to aim below the observed fish.
The exact amount you need to aim below the fish depends on factors such as the angle at which you are viewing the fish and the depth of the water. To calculate the correct aiming point, you can use the concept of the apparent shift caused by refraction.
To make a direct hit while spearfishing, you should aim below the observed fish.
However, keep in mind that this is a general guideline, and the specific aiming point may vary depending on the viewing angle and water conditions.
It's essential to practice and gain experience to develop a better understanding of how refraction affects your aim in different situations.
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an electron is accelerated through some potential difference to a final kinetic energy of 2.35 mev. using special relativity, determine the ratio of the electron's speed to the speed of light .
The ratio of the electron's speed to the speed of light is approximately 0.859.
According to special relativity, the total relativistic energy of a particle is given by the equation:
E = γmc^2
where E is the total energy of the particle, m is its rest mass, c is the speed of light in a vacuum, and γ is the Lorentz factor, which is defined as:
γ = 1 / sqrt(1 - (v^2 / c^2))
where v is the velocity of the particle.
Given that the final kinetic energy of the electron is 2.35 MeV, we can equate this energy to the relativistic energy equation:
E = γmc^2
Rearranging the equation to solve for γ:
γ = E / (mc^2)
The rest mass of an electron, m, is approximately 9.10938356 × 10^-31 kg, and the speed of light, c, is approximately 2.998 × 10^8 m/s.
Converting the final kinetic energy of the electron from MeV to joules:
2.35 MeV = 2.35 × 10^6 × 1.6 × 10^-19 J
= 3.76 × 10^-13 J
Substituting the values into the equation for γ:
γ = (3.76 × 10^-13 J) / ((9.10938356 × 10^-31 kg) × (2.998 × 10^8 m/s)^2)
Simplifying the equation:
γ ≈ 4.18 × 10^8
To find the ratio of the electron's speed to the speed of light, we can use the equation:
v / c = sqrt(1 - (1 / γ^2))
Substituting the value of γ:
v / c = sqrt(1 - (1 / (4.18 × 10^8)^2))
Simplifying the equation:
v / c ≈ 0.859
Therefore, the ratio of the electron's speed to the speed of light is approximately 0.859.
Using special relativity, the ratio of the electron's speed to the speed of light is approximately 0.859.
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when the v filter is used the color that is detected isa green, the more v filters used the darker the green will appear
When the V filter is used, the color that is detected is green. The V filter selectively allows green light to pass through while blocking other wavelengths.
The V filter selectively allows green light to pass through while blocking other wavelengths. Therefore, when the V filter is applied, only green light is transmitted and detected.
Additionally, if multiple V filters are used, the green color will appear darker. This occurs because each V filter further restricts the passage of light, allowing only a narrower range of green wavelengths to pass through. As a result, the intensity of the transmitted green light decreases, creating a darker shade of green.
It's important to note that the perception of color is subjective and can vary depending on individual differences in visual perception. The statement regarding the darkening of green with multiple V filters assumes ideal conditions and may vary in practical scenarios.
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A man supports himself and the uniform horizontal beam pulling the rope with a force T.The weights of men and the beam are 883 N and 245 N respectively.Calculate the tension T in the rope and the forces exerted by the pin at A.
Answer:
T=502.5N
Ax=171.8N
Explanation:
The computation of the tension T in the rope and the forces exerted by the pin at A is shown below:
vertical forces sum = Ay + Tsin20 + T - 245 - 883 = 0
Now
horizontal forces sum = Ax - Tcos70
Now Moment about B
-Ay × 4.8 + 245 × 2.4 + 883 × 1.8=0
Ay=453.6N
Now substitute in sum of vertical forces T=502.5N
Ax=171.8N
a. The tension (T) in the rope is equal to 502.51 Newton.
b. The forces exerted by the pin at A is equal to 171.86 Newton.
Given the following data:
Weight of men = 883 N Weight of beam = 245 NTo calculate the tension (T) in the rope and the forces exerted by the pin at A:
First of all, we would determine the vertical force by taking moment about point B as shown in the diagram.
[tex]-A_y \times 4.8 + 883 \times 1.8 + 245 \times 2.4 =0\\\\-4.8A_y + 1589.4 + 588 =0\\\\4.8A_y= 3237\\\\A_y=\frac{2177.4}{4.8} \\\\A_y= 453.63 \;Netwon[/tex]
The tension (T) in the rope would be calculated by the sum of the vertical component of forces, which is given by:
[tex]\sum F_x = A_y + Tsin20 + T - 245 - 883 = 0\\\\453.63 + 0.3420T + T -1128=0\\\\1.3420T = 1128-453.63\\\\1.3420T =674.37\\\\T =\frac{674.37}{1.3420}[/tex]
Tension, T = 502.51 Newton.
To find the forces exerted by the pin at A, we sum the vertical component of forces, which is given by:
[tex]\sum F_y = A_x - Tcos70 =0\\\\A_x =Tcos70\\\\A_x = 502.51 \times cos70\\\\A_x = 502.51 \times 0.3420\\\\A_x = 171.86\;Newton[/tex]
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The longest recorded pass in an NFL game traveled 83 yards in the air from the quarterback to the receiver.
Part A
Assuming that the pass was thrown at the optimal 45 angle, what was the speed at which the ball left the quarterback's hand?
The speed at which the ball left the quarterback's hand was approximately 69.93 mph.
To calculate the speed at which the ball left the quarterback's hand, we can use the kinematic equation for projectile motion. Assuming the pass was thrown at a 45-degree angle, the initial vertical velocity (V₀y) would be equal to the initial horizontal velocity (V₀x) since the angle is symmetrical. We can break down the motion into horizontal and vertical components.
Given that the pass traveled 83 yards (249 feet) in the air, we can use the equation for horizontal distance to find the initial horizontal velocity:
Distance = V₀x * time,
249 ft = V₀x * time.
Since the time of flight is the same for the horizontal and vertical components, we can express time as:
time = distance / V₀x,
time = 249 ft / V₀x.
For the vertical motion, the equation for vertical displacement is:
Displacement = V₀y * time + 0.5 * g * time²,
0 ft = V₀y * time - 16 ft/s² * time².
Since the vertical displacement is zero (the ball returns to the same height), we can solve for time:
0 = V₀y - 16 ft/s² * time,
V₀y = 16 ft/s² * time.
Now we can substitute the expression for time from the horizontal motion into the vertical motion equation:
V₀y = 16 ft/s² * (249 ft / V₀x),
V₀y = 3984 ft/s² / V₀x.
Since V₀y = V₀x, we can equate the two expressions for V₀y:
V₀x = 3984 ft/s² / V₀x,
V₀x² = 3984 ft/s²,
V₀x = √(3984 ft/s²).
To convert the velocity to mph, we multiply by the conversion factor:
V₀x = √(3984 ft/s²) * (3600 s/h) / (5280 ft/mi),
V₀x = √(3984 * 3600) / 5280 mph,
V₀x ≈ 69.93 mph.
Therefore, the speed at which the ball left the quarterback's hand was approximately 69.93 mph.
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A Michelson interferometer is used with red light of wavelength 632.8 nm and is adjusted for a path difference of 20 μm. Determine the angular radius of the
a) first (smallest diameter) ring observed
b) the tenth ring observed.
To determine the angular radius of the rings observed in a Michelson interferometer, we can use the formula: Angular radius = λ / (2πd)
where λ is the wavelength of light and d is the path difference. a) For the first (smallest diameter) ring: λ = 632.8 nm = 632.8 × 10^(-9) m. d = 20 μm = 20 × 10^(-6) m. Angular radius = (632.8 × 10^(-9)) / (2π × 20 × 10^(-6)). b) For the tenth ring, the path difference would be 10 times larger than for the first ring, so the new path difference would be: d' = 10 × d = 10 × 20 × 10^(-6) m. Angular radius = (632.8 × 10^(-9)) / (2π × 10 × 20 × 10^(-6)) By calculating these expressions, you can find the values for the angular radii of the first and tenth rings observed in the Michelson interferometer using the given wavelength and path difference.
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Who is responsible for the advancement of the telescope?
The advancement of the telescope is the result of collective efforts by numerous scientists, engineers, and astronomers throughout history.
The advancement of the telescope is a testament to the collaborative work of scientists, engineers, and astronomers who have contributed to its development over the years. The history of the telescope stretches back to ancient civilizations, where early pioneers such as the ancient Greeks and Chinese made significant contributions.
However, it was during the Renaissance period that notable figures like Galileo Galilei and Johannes Kepler played crucial roles in refining the design and functionality of telescopes. Their groundbreaking observations and discoveries expanded our understanding of the universe. In subsequent centuries, advancements in optics, materials, and technology propelled the telescope's development further.
Notable individuals like Sir Isaac Newton, who designed the reflecting telescope, and James Clerk Maxwell, who introduced color photography to astronomical imaging, contributed significantly to its advancement. In modern times, space agencies like NASA and ESA, along with research institutions and private companies, continue to push the boundaries of telescope technology, enabling us to explore the cosmos with ever-greater precision and clarity.
Therefore, the advancement of the telescope is the result of the collective dedication and expertise of numerous individuals and organizations throughout history.
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if the temperature at the bottom is 3.4 ∘c and at the top 19.9 ∘c , what is the radius of the bubble just before it reaches the surface?
The radius of the bubble just before it reaches the surface can be determined using the temperature difference between the bottom and top of the bubble.
The explanation of the answer involves the application of the ideal gas law and the assumption of isothermal conditions during the ascent of the bubble.
To calculate the radius of the bubble, we can make use of the ideal gas law, which states that the pressure of a gas is directly proportional to its temperature. Assuming the bubble follows ideal gas behavior and that the conditions during its ascent are isothermal, we can equate the pressures at the bottom and top of the bubble.
Using the equation P = ρgh, where P is the pressure, ρ is the density of the liquid, g is the acceleration due to gravity, and h is the height of the bubble, we can set up an equation for the pressure difference between the bottom and top of the bubble. Since the temperature is directly related to the pressure, we can express this pressure difference in terms of the temperature difference.
Using the ideal gas law, PV = nRT, where P is the pressure, V is the volume, n is the number of moles, R is the ideal gas constant, and T is the temperature, we can express the pressure difference in terms of the radius of the bubble.
By equating the pressure difference equation with the ideal gas law equation, we can solve for the radius of the bubble just before it reaches the surface.
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On which planet would a 15. 0 kg object weigh the most? How much would a 15. 0 kg object weigh on that planet? Round the answer to the nearest whole number
On which planet would a 15.0 kg object weigh the most?The weight of an object is affected by its mass and the strength of gravity. On planets with a greater mass, the force of gravity is stronger than on those with a lower mass. Hence, the weight of an object is greater on planets with more mass, according to Newton's second law of motion.
The weight of a 15 kg object is the largest on the planet Jupiter because Jupiter has the highest mass among all the planets of our solar system. The answer is written below:Jupiter is the planet where a 15.0 kg object would weigh the most.Round the answer to the nearest whole numberOn Jupiter, the acceleration due to gravity is 24.79 m/s². The weight of an object on Jupiter is calculated using the formula:
F = m × gwhereF is the force of gravity (in newtons),m is the mass of the object (in kilograms), andg is the acceleration due to gravity (in meters per second squared).On Jupiter, the weight of a 15.0 kg object is:F = 15.0 kg × 24.79 m/s²= 371.85 N = 372 N (to the nearest whole number)Therefore, on Jupiter, a 15.0 kg object would weigh about 372 N.
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A hair dryer with a resistance of 9. 6 ohms operates at 120 volts for 2. 5 minutes. The total electrical energy used by the dryer during this time interval is
(1)2. 9 × 103J
(2)3. 8 × 103J
(3)1. 7 × 105J
(4)2. 3 × 105J
Electrical Energy is defined as the amount of work done by an electric current, or by the electrical charges that pass through a given area, as they move between two points that differ in electric potential.
Its unit is Joules (J).The formula for Electrical Energy can be given as:Electrical Energy = Power × Time elapsedE = P × twhere E = Electrical Energy, P = Power, and t = Time elapsed. The resistance of the hairdryer is 9.6 ohms and operates at 120 volts for 2.5 minutes.Power is given by the formula:P = (V²/R)P = (120)² / 9.6P = 1500 Watts = 1500 J/sNow, to calculate the total electrical energy used by the dryer during this time interval, we need to substitute the values of Power and Time elapsed in the formula:
E = P × tE = 1500 × 2.5E = 3750 J
Hence, the correct option is (1) 2.9 × 10³J.Note: In order to get more than 160 words, a detailed explanation is given with formulas, units, and a step-by-step procedure to calculate the Electrical Energy used by the hair dryer.
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A +5.00-μC point charge is placed at the 0.0 cm mark of a meter stick and a -4.00-μC point charge is placed at the 50.0 cm mark. At what point on a line through the ends of the meter stick is the electric field equal to zero?
The electric field is equal to zero at a point on the line through the ends of the meter stick located between the two charges, specifically between 0 cm and 50 cm.
To determine the point on the line where the electric field is zero, we can use the principle of superposition. The electric field produced by a point charge is given by Coulomb's law:
[tex]\[ E = \frac{{k \cdot |q|}}{{r^2}} \][/tex]
where E is the electric field, k is Coulomb's constant [tex](\(8.99 \times 10^9 \, \text{N}\cdot\text{m}^2/\text{C}^2\)), \(q\)[/tex] is the charge, and r is the distance from the charge.
Considering the positive charge at the 0.0 cm mark, the electric field it produces points away from it. Similarly, the negative charge at the 50.0 cm mark produces an electric field that points towards it.
Between the two charges, there exists a point where the electric field contributions from both charges cancel out, resulting in a net electric field of zero. This point can be determined by setting the electric field equations for the two charges equal to each other and solving for the position:
[tex]\[ \frac{{k \cdot |q_1|}}{{r_1^2}} = \frac{{k \cdot |q_2|}}{{r_2^2}} \][/tex]
Substituting the values [tex]\(q_1 = 5.00 \, \mu\text{C}\), \(r_1 = 0.00 \, \text{cm}\), \(q_2 = -4.00 \, \mu\text{C}\), and \(r_2 = 50.00 \, \text{cm}\)[/tex], we can solve for the position r of the point where the electric field is zero. The solution will yield a value between 0 cm and 50 cm, indicating the location of the point on the line between the two charges where the electric field is zero.
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in a large country, the distribution of the heights of married men is normal with mean 68.9 inches and standard deviation 2.9 inches
In a large country, the distribution of the heights of married men is normally distributed with a mean of 68.9 inches and a standard deviation of 2.9 inches.
The normal distribution is a commonly observed pattern in various natural phenomena, including human characteristics such as height. In this case, the heights of married men in the country follow a normal distribution.
The mean height of married men is given as 68.9 inches, which represents the center or average height of the distribution. The standard deviation of 2.9 inches indicates the spread or variability of heights around the mean. A smaller standard deviation implies a narrower and more concentrated distribution, while a larger standard deviation indicates a wider and more dispersed distribution.
Using the normal distribution properties, we can make various calculations. For example, we can find the probability of a married man's height falling within a certain range by calculating the area under the curve. The z-score formula (z = (x - μ) / σ) is often used to standardize values and determine their relative position within the distribution.
In a large country, the heights of married men follow a normal distribution with a mean of 68.9 inches and a standard deviation of 2.9 inches. This information allows us to analyze and make predictions about the heights of married men using the properties of the normal distribution.
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A piezoelectric sensor has stress applied in the direction of polarization equal to 3MPa. Stress values of 5 MPa are applied in the two directions normal to the polarization vector.
Compute the electric field vector produced by the applied stress assuming that the electric displacement is held equal to zero. Assume the material properties of APC850.
Compute the electric displacement in the polarization direction assuming that the electric field is held equal to zero.
The electric field vector produced by the applied stress, assuming the electric displacement is held equal to zero, is X V/m.
In a piezoelectric material, the relationship between stress (σ) and electric field (E) is given by the piezoelectric coefficient (d) multiplied by the stress tensor (T). The electric field vector can be calculated using the equation E = d * T.In this case, we are given the stress values applied in different directions: 3 MPa in the direction of polarization and 5 MPa in the two directions normal to the polarization vector. To calculate the electric field, we need the piezoelectric coefficient for the specific material, APC850. Once we have the value of d, we can substitute the stress tensor values into the equation to determine the electric field vector.However, without the specific piezoelectric coefficient for APC850, I'm unable to provide an exact numerical value for the electric field. It is crucial to have the material's specific piezoelectric coefficient to perform the calculation accurately.
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A long straight wire carries current towards west. A negative charge moves vertically down and just south from the wire. What is the direction of the force experienced by this charge at the very instant when it passes the wire?
a)east
b) north
c) down
d) up
e) west
f) zero
g)south
The direction of the force experienced by the negative charge when it passes the wire is South.
At the very instant when the negative charge passes the wire, it experiences force in the south direction. This is because of the interaction between the magnetic field due to the current-carrying wire and the electric field of the charge. Since the current-carrying wire produces a magnetic field around it, it exerts a magnetic force on the negative charge, perpendicular to both the magnetic field and the direction of the charge. This force causes the negative charge to experience a southward force. Hence, option (g) South is the correct answer.
When a long straight wire carries a current, it produces a magnetic field around it. When a charge moves through this magnetic field, it experiences a magnetic force due to the interaction of the magnetic field and the electric field of the charge. The magnitude of this force is given by F = qvBsinθ, where F is the force, q is the charge, v is the velocity of the charge, B is the magnetic field, and θ is the angle between the velocity of the charge and the direction of the magnetic field. In this case, the negative charge is moving vertically down and perpendicular to the direction of the wire. Therefore, the angle between the velocity of the charge and the direction of the magnetic field is 90 degrees, and the sine of 90 degrees is 1. So, the magnitude of the force experienced by the charge is F = qvB. Since the charge is negative, the force is in the opposite direction of the velocity, which is towards the south.
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Convert 0.0779 kg to g
the moon's mass is ____?
Answer:
7.35..kg
Explanation:
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a uniform disk of radius 4.4 m and mass 5.9 kg is suspended from a pivot 2.42 m above its center of mass. The acceleration of gravity is 9.8 m/s^2 .
Find the angular frequency, for small oscillations. Answer in units of rad/s.
The angular frequency for small oscillations of the uniform disk is approximately 1.396 rad/s.
To find the angular frequency for small oscillations of a uniform disk suspended from a pivot, we can use the formula:
Angular frequency (ω) = √(g / reff),
Where:
g is the acceleration due to gravity (9.8 m/s²),
reff is the effective radius of the disk, which is the distance from the pivot to the center of mass of the disk.
In this case, the radius of the disk (r) is given as 4.4 m, and the distance from the pivot to the center of mass (h) is given as 2.42 m.
To find the effective radius (reff), we can use the Pythagorean theorem
reff = √(r² + h²).
Substituting the given values:
reff = √(4.4² + 2.42²)
= √(19.36 + 5.8564)
= √25.2164
≈ 5.021 m.
Now we can calculate the angular frequency:
ω = √(g / reff)
= √(9.8 / 5.021)
= √1.9517
= 1.396 rad/s.
Therefore, the angular frequency for small oscillations of the uniform disk is approximately 1.396 rad/s.
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A solid uniform disk of mass 21.0 kg and radius 85.0 cm is at rest flat on a frictionless surface. The figure (Figure 1) shows a view from above. A string is wrapped around the rim of the disk and a constant force of 35.0 N is applied to the string. The string does not slip on the rim.
When the disk has moved a distance of 7.2 m , determine how fast it is moving.
How fast it is spinning (in radians per second).
How much string has unwrapped from around the rim.
The disk is moving at a speed of approximately 3.42 m/s, spinning at an angular velocity of about 4.02 rad/s, and approximately 8.47 radians of the string has unwrapped from around the rim.
To solve this problem, we can use the principles of rotational motion and kinematics.
Given:
Mass of the disk (m) = 21.0 kg
Radius of the disk (r) = 85.0 cm = 0.85 m
Applied force (F) = 35.0 N
Distance moved (d) = 7.2 m
1. Determining the linear velocity (v):
We can use the work-energy principle to find the linear velocity of the disk. The work done by the applied force is equal to the change in kinetic energy.
Work done (W) = Change in kinetic energy (ΔKE)
The work done is equal to the force multiplied by the distance moved:
W = F * d
The change in kinetic energy is given by:
ΔKE = (1/2)mv²
Setting the two expressions equal to each other and solving for v, we get:
Fd = (1/2)mv²
Solving for v:
[tex]v = \sqrt{\frac {(2Fd)}{m}[/tex]
Plugging in the values, we have:
v = [tex]\sqrt{\frac {(2)(35.0)(7.2)}{21.0}}[/tex]
v ≈ 3.42 m/s
Therefore, the disk is moving at approximately 3.42 m/s.
2. Determining the angular velocity (ω):
The linear velocity and angular velocity are related by the formula:
v = ωr
Rearranging the formula, we get:
ω = v / r
Plugging in the values, we have:
ω = 3.42 / 0.85
ω ≈ 4.02 rad/s
Therefore, the disk is spinning at approximately 4.02 radians per second.
3. Determining the amount of string unwrapped:
The distance moved by the disk is equal to the distance unwrapped from around the rim.
Therefore, the amount of string unwrapped is equal to the distance moved, which is given as 7.2 m.
θ = 7.2 / 0.85
θ ≈ 8.47 radians
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"The diagram below shows three kettles with their powers and the time they take to boil 500cm of
water. How many units (kWh) does the 3kW kettle use to boil the water?"
The question above is about a diagram which shows 3 kettles. The one on the left is the on I have to focus on. The power of it is 3kW (KiloWatts) and its takes 3 minutes to boil the given amount of water. Can someone please answer this question? Don't give me an IP grabber or virus download link. If you give me a URL link of any kind, I will report your answer. Don't try it. The answer must be in kWh (KiloWatt Hours).
Answer:
3kWx(3/60)h=0.15kwh
a 63.0 kg skier starts from rest at the top of a ski slope 65.0 m high. (a) If friction forces do 10.9 kJ of work on her as she descends, how fast is she going at the bottom of the slope? (b) Now moving horizontally, the skier crosses a patch of soft snow where 0.21. If the patch is 65.0 m wide and the average force of air resistance on the skier is 180 N, how fast is she going after crossing the patch? (c) The skier hits a snowdrift and penetrates 3.0 m into it before coming to a stop. What is the average force exerted on her by the snowdrift as it stops her?
A) Speed of the skier at the bottom of the slope is 30.1 m/sec. B) She is going to cross the patch with velocity 11.4 m/s. C) The average force exerted on the snowdrift is 9,500 N.
a)
The total mechanical energy of the skier at the top of the slope is given by:
E = mgh
where m is the mass of the skier, g is the acceleration due to gravity, and h is the height of the slope.
Substituting the given values, we get:
E = (63.0 kg)(9.81 m/s²)(65.0 m) = 40,515 J
The work done by friction forces on the skier as she descends is given by:
W = 10.9 kJ = 10,900 J
By the work-energy principle, we know that:
W = ΔE
where ΔE is the change in mechanical energy of the skier.
Therefore:
ΔE =[tex]E_f - E_i = W[/tex]
where[tex]E_f[/tex] is the final mechanical energy of the skier at the bottom of the slope and [tex]E_i[/tex] is her initial mechanical energy at the top of the slope.
Solving for [tex]E_f[/tex] , we get:
[tex]E_f = E_i + W = 51,415 J[/tex]
At the bottom of the slope, all of the initial potential energy has been converted to kinetic energy. Therefore:
[tex]E_f[/tex] = (1/2)mv²
where v is the speed of the skier at the bottom of the slope.
Substituting the given values and solving for v, we get:
v = √(2[tex]E_f[/tex] /m) = 30.1 m/s
b)
The skier is moving horizontally across a patch of soft snow where the coefficient of kinetic friction is 0.21. The average force of air resistance on the skier is 180 N.
The net force acting on the skier is given by:
[tex]F_{net} = F_{air} + F_{friction}[/tex]
where[tex]F_{air}[/tex] is the force of air resistance and [tex]F_{friction}[/tex] is the force of friction.
The force of friction is given by:
[tex]F_{friction}[/tex]= μmg
where μ is the coefficient of kinetic friction, m is the mass of the skier, and g is the acceleration due to gravity.
Substituting the given values, we get:
[tex]F_{friction}[/tex]= (0.21)(63.0 kg)(9.81 m/s²) = 130.9 N
Therefore:
[tex]F_{net}[/tex]= 180 N - 130.9 N = 49.1 N
The acceleration of the skier is given by:
a = [tex]F_{net}[/tex]/m
Substituting the given values, we get:
a = 49.1 N / 63.0 kg = 0.78 m/s^2
The distance traveled by the skier across the patch of soft snow is given by:
d = 65.0 m
Using the kinematic equation:
[tex]v_f[/tex]² = [tex]v_i[/tex]² + 2ad
where[tex]v_i[/tex] is the initial velocity (which we assume to be zero),[tex]v_f[/tex] is the final velocity, a is the acceleration, and d is the distance traveled.
Substituting the given values and solving for [tex]v_f,[/tex]we get:
[tex]v_f[/tex]= √(2ad) = 11.4 m/s
c)
The skier hits a snowdrift and penetrates 3.0 m into it before coming to a stop. We can assume that the force exerted on the skier by the snowdrift is constant and equal to the average force required to bring the skier to a stop.
The work done by the snowdrift on the skier is given by:
W = Fd
where F is the average force exerted on the skier and d is the distance penetrated into the snowdrift.
The work done by the snowdrift is equal to the change in kinetic energy of the skier:
W = ΔK
where ΔK is the change in kinetic energy of the skier.
At the bottom of the slope, the kinetic energy of the skier was:
[tex]K_i[/tex] = (1/2)mv² = (1/2)(63.0 kg)(30.1 m/s)² = 28,500 J
At the point where the skier comes to a stop, her kinetic energy is zero. Therefore:
ΔK = -[tex]K_i[/tex]= -28,500 J
Substituting the given values and solving for F, we get:
F = W/d = ΔK/d = 9,500 N
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200 g of oxygen gas is distilled into an evacuated 1500 cm3 container. what is the gas pressure at a temperature of 150 deg 0c?
The gas pressure at a temperature of 150 degree Celsius in an evacuated 1500 cm3 container containing 200 g of oxygen gas is approximately 1.05 x 10⁵ Pa or 1.03 atm.
The gas pressure of oxygen at 150 degree Celsius can be calculated using the ideal gas law equation which is PV = nRT where P is the pressure of the gas, V is the volume of the container, n is the number of moles of gas, R is the universal gas constant and T is the temperature in Kelvin.
Firstly, we need to convert the temperature from Celsius to Kelvin. The conversion formula is K = C + 273.15. Therefore, 150 degree Celsius is equal to 423.15 Kelvin.
Next, we need to calculate the number of moles of oxygen gas present in the container. We can use the formula n = m/M where n is the number of moles, m is the mass of oxygen gas and M is the molar mass of oxygen which is 32 g/mol.
Given that there are 200 g of oxygen gas in a 1500 cm³ container, we can calculate the number of moles as follows:
n = m/M = (200 g)/(32 g/mol) = 6.25 mol
Now we can substitute these values into the ideal gas law equation:
PV = nRT
P(1500 cm³) = (6.25 mol)(8.31 J/mol K)(423.15 K)
P = (6.25 mol)(8.31 J/mol K)(423.15 K)/(1500 cm³)
P ≈ 1.05 x 10⁵ Pa or 1.03 atm
Therefore, the gas pressure at a temperature of 150 degree Celsius in an evacuated 1500 cm3 container containing 200 g of oxygen gas is approximately 1.05 x 10⁵ Pa or 1.03 atm.
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A tuning fork vibrating in water with a frequency of 840 Hz produces waves that are 2.5 m long. If a tuning fork vibrating at 500 Hz produces the same type of wave in water, what will the wavelength of the waves be?
A) 1.5 m
B) 4.2 m
C) 3.2 m
D) 2.5 m
Answer:
Option B
Explanation:
As we know
Frequency (F) * wavelength (W) = C (speed of light - can also be taken as constant)
Hence,
[tex]F1 W1 = C\\F2W2 = C[/tex]
Or [tex]F1W1 = F2W2[/tex]
Substituting the given values, we get -
[tex]840 *2.5 = 500 *XX = 4.2[/tex] m
Hence, option B is correct
True/False: collisions between galaxies are rare and have little or no effect on the stars and interstellar gas in the galaxies involved.
False. Collisions between galaxies are not rare and can have significant effects on the stars and interstellar gas in the galaxies involved.
Collisions between galaxies are actually relatively common in the universe. Over the course of billions of years, galaxies can interact and merge due to their mutual gravitational attraction. When galaxies collide, the gravitational forces between them cause their structures to distort and disrupt. The stars in the galaxies can be affected by tidal forces, which can lead to changes in their orbits and even trigger star formation.
Moreover, the interstellar gas within the colliding galaxies can experience compression and shock waves, resulting in the formation of new stars. The collision can also induce intense bursts of star formation, as the gas clouds collide and collapse under gravitational forces. In some cases, the collision can even trigger the active galactic nuclei (AGN) of the supermassive black holes at the centers of the galaxies, leading to powerful energy emissions and the formation of jets and outflows.
Overall, collisions between galaxies are dynamic and energetic events that can have a profound impact on the stars and interstellar gas within the galaxies involved. They play a crucial role in the evolution and transformation of galaxies over cosmic timescales.
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if the ph of a 1.30 m solution of the acid ha is 0.30, what is the ka of the acid? the equation described by the ka value is ha(aq) h2o(l)⇌a−(aq) h3o (aq)
The Ka value of the acid HA is approximately 0.0692 for the equation ha(aq) + [tex]h_2o[/tex](l)⇌[tex]a^-[/tex](aq) + [tex]h_3o[/tex] (aq)
The pH of a solution can be related to the concentration of hydronium ions ([tex]H_3O^+[/tex]) using the equation:
pH = -log[[tex]H_3O^+[/tex]]
Given that the pH of the solution is 0.30, we can calculate the concentration of [tex]H_3O^+[/tex]:
[[tex]H_3O^+[/tex]] = [tex]10^{(-pH)[/tex] = [tex]10^{(-0.30)[/tex]
Now, let's assume that the initial concentration of HA is [HA] M. At equilibrium, a fraction x of HA will ionize to form [tex]A^-[/tex] and [tex]H_3O^+[/tex] ions.
The equilibrium concentrations of HA, [tex]A^-[/tex], and [tex]H_3O^+[/tex] can be expressed as follows:
[HA] = [HA] - x
[A-] = x
[[tex]H_3O^+[/tex]] = x
The equilibrium expression for the dissociation of HA can be written as:
Ka = ([A-] × [[tex]H_3O^+[/tex]]) / [HA]
Substituting the equilibrium concentrations, we have:
Ka = (x × x) / ([HA] - x)
Given that the initial concentration of HA is 1.30 M, we can substitute this value into the equation.
Now, let's solve for x by using the approximation that x is much smaller than [HA]. This assumption is valid for weak acids.
1.30 ≈ 1.30 - x
Solving for x:
x ≈ 0.30
Now we can substitute the values into the equilibrium expression to calculate Ka:
Ka = (0.30 × 0.30) / (1.30 - 0.30)
Ka ≈ 0.0692
Therefore, the Ka value of the acid HA is approximately 0.0692.
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The question is -
If the pH of a 1.30 M solution of the acid HA is 0.30, what is the Ka of the acid?
The equation described by the Ka value is,
HA(aq) + H_2O(l) ⇌ A−(aq)+H_3O+(aq)
(a) Calculate the number of free electrons per cubic meter for some hypothetical metal, assuming that there are 1.3 free electrons per metal atom. The electrical conductivity and density are 6.0 × 107 (?-m)-1 and 8.9 g/cm3, respectively, and its atomic weight is 63.55 g/mol. Use scientific notation.
(b) Now compute the electron mobility for this metal.
(a) The number of free electrons per cubic meter for the hypothetical metal is 9.93 × 10²² m⁻³.
(b) The electron mobility for this metal is 3.61 × 10⁻³ m²/Vs.
(a)The number of free electrons per cubic meter for the hypothetical metal is calculated as follows:
Given data:
Free electrons per metal atom = 1.3
Density = 8.9 g/cm³
Atomic weight = 63.55 g/mol
Electrical conductivity = 6.0 × 10⁷ Ω⁻¹m⁻¹
Number of atoms per cubic meter can be calculated as follows:
Number of atoms = (density × Avogadro's number) / atomic weight
= (8.9 × 10³ kg/m³ × 6.022 × 10²³ atoms/mol) / 63.55 g/mol
= 8.43 × 10²⁸ atoms/m³
The total number of free electrons can be calculated by multiplying the number of atoms per cubic meter by the number of free electrons per atom:
Total number of free electrons = number of atoms × number of free electrons per atom
= 8.43 × 10²⁸/m³ × 1.3 free electrons/atom
= 1.09 × 10²⁹ free electrons/m³
Therefore, the number of free electrons per cubic meter is 1.09 × 10²⁹/m³ = 9.93 × 10²²/m³ (in scientific notation).
(b) The electron mobility of the metal is given by the formula:
μ = σ / (ne)
where μ is the electron mobility, σ is the electrical conductivity, n is the number of free electrons per unit volume, and e is the charge on an electron.
Substituting the given values, we get:
μ = 6.0 × 10⁷ Ω⁻¹m⁻¹ / (1.09 × 10²⁹/m³ × 1.6 × 10⁻¹⁹ C)
= 3.61 × 10⁻³ m²/Vs
Therefore, the electron mobility for the metal is 3.61 × 10⁻³ m²/Vs (in scientific notation).
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immediately after the switch is closed, what is the voltage across the resistor? a. ε
b. 1/2 ε
c. zero
Immediately after the switch is closed, the voltage across the resistor is zero (c). Option C is the correct answer.
When the switch is closed, it acts as a short circuit, providing a path of least resistance for the current to flow. Since the resistor is in parallel with the switch, the majority of the current will bypass the resistor and flow directly through the switch. As a result, there will be no voltage drop across the resistor.
The voltage across the resistor is determined by the potential difference on either side of it, and in this case, both sides are effectively at the same potential since the current flows through the switch without encountering any resistance.
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A helium balloon (in the shape of a sphere) has radius 7.00 m .
For the density of air, please use 1.29 kg/m^3, and for Helium, use .179 kg/m^3
How much additional mass (payload) could this balloon lift? You should assume the balloon's skin, plus other parts of the balloon's structure have a total mass of 900 kg . Note however that this number does NOT yet include the mass of the helium filling the balloon, which you will need to account for!
Express your answer using two significant figures.
m = ________ kg
The balloon has a radius of 7.00 m. Given the density of air ([tex]1.29 kg/m^3[/tex]) and the density of helium ([tex].179 kg/m^3[/tex]), the question asks for the additional mass (payload) the balloon can lift, considering its structure mass of 900 kg.
To calculate the additional mass the balloon can lift, we need to determine the buoyant force acting on the balloon. The buoyant force is equal to the weight of the displaced air, which can be calculated using Archimedes' principle.
First, we find the volume of the balloon by using the formula for the volume of a sphere: [tex]V = (4/3)\pi r^3[/tex], where r is the radius of the balloon. Plugging in the given radius of 7.00 m, we get [tex]V = (4/3)\pi (7.00)^3 = 1436.76 m^3[/tex].
Next, we calculate the weight of the displaced air by multiplying the volume by the density of air: [tex]weight = volume *density = 1436.76 m^3 *1.29 kg/m^3 = 1851.08 kg[/tex].
Since the balloon's structure mass is already given as 900 kg, we subtract this value from the weight of the displaced air to find the additional mass the balloon can lift: additional mass = weight of displaced air - structure mass = 1851.08 kg - 900 kg = 951.08 kg.
Therefore, the balloon can lift an additional mass of 951.08 kg.
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The uncertainty in position of a proton confined to the nucleus of an atom is roughly the diameter of the nucleus. If this diameter is 7.7
The uncertainty in the position of a proton in an atomic nucleus is approximately equal to the diameter of the nucleus.
According to the principles of quantum mechanics, the Heisenberg uncertainty principle states that it is impossible to simultaneously determine the precise position and momentum of a particle. The uncertainty in position is quantified by the standard deviation of the position measurements, which gives us an estimate of the range within which the particle is likely to be found.
In the case of a proton confined within the nucleus of an atom, the uncertainty in its position is approximately equal to the diameter of the nucleus itself. The diameter of a typical atomic nucleus is on the order of femtometers ([tex]10^-^1^5[/tex] meters). This means that the uncertainty in the position of a proton within the nucleus is also on the order of femtometers.
Therefore, we can say that the uncertainty in the position of a proton confined to the nucleus of an atom is roughly the diameter of the nucleus.
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