seab physics test 2 pre assignments
Max is pushing on the edge (2.4 m from the center) of the merry-go-round to make it rotate. Maya is riding on the merry-go-round, sitting 1.2 m from the center. If Max is pushing the merry-go-round at 1.4 m/s, how fast is Maya moving? 0.70 m/s 2.1 m/s 1.4 m/s 4.0 m/s 0.58 m/s
.70 m/s
Max (15 kg) and Maya (12 kg) are riding on a merry-go-round that rotates at a constant speed. Max is sitting on the edge of the merry-go-round, 2.4 m from the center, and Maya is sitting somewhere between the edge and the center. The merry-go-round is a solid disk with a radius of 2.4 m, a mass of 230 kg, and is rotating at a constant rate of 0.75 rev/s. The system, which includes Max, Maya, and the merry-go-round, has 8700 J of rotational kinetic energy. How far away is Maya from the center of the merry-go-round? 1.5 m 1.7 m 50 m 2.9 m 1.9 m
1.7 m
Max (15 kg) and Maya (12 kg) are riding on a merry-go-round that rotates at a constant speed. Max is sitting on the edge of the merry-go-round, 2.4 m from the center, and Maya is 1.2 m from the center. Considering Max and Maya to be one system of masses, what is their moment of inertia measured with respect to the center of the merry-go-round? 104 kg•m2 86 kg•m2 17 kg•m2 50 kg•m2 1500 kg•m2
104 kg•m2
You are riding on a roller coaster that starts from rest at a height of 25.0 m and moves along a frictionless track. How fast are you moving when you reach the top of the loop, at point B? The figure shows a path of a car on a roller coaster. The path starts at the highest point of the coaster, A, 25.0 meters above the ground, then goes downwards and to the right to the point 3.00 meters above the ground, then goes upwards and to the right, reaches the second highest point, then goes downwards and to the right, reaches the ground, passes a circular loop and goes horizontally rightwards. The highest point of the loop, B, is 12.0 meters above the ground. The second highest point is 4.00 meters above the point B. 26.9 m/s 16.0 m/s 13.3 m/s 20.3 m/s
16.0 m/s
Earth is 149.6 billion meters from the Sun and takes 365 days to make one complete revolution around the Sun. Mars is 227.9 billion meters from the Sun and has an orbital period of 687 days. What is the ratio of Earth's centripetal acceleration to Mars's centripetal acceleration? 0.430 1.24 2.33 0.809 1.88
2.33
Max and Maya are riding on a merry-go-round that rotates at a constant speed. If the merry-go-round makes 3.5 revolutions in 9.2 seconds, what is its angular speed? 5.1 rad/s 0.38 rad/s 22 rad/s 2.4 rad/s 0.0066 rad/s
2.4 rad/s
On a snowy day, Max (mass = 15 kg) pulls his little sister Maya in a sled (combined mass = 20 kg) through the slippery snow. Max pulls on the sled with 12 N of force, directed at an angle of 15° above the ground. When he comes to a recently plowed section of road, he continues to pull the sled with the same force across the road while the road exerts a frictional force of 4 N on sled. If the sled's speed is 1.5 m/s as Max pulls it onto the road, what is the sled's speed after Max pulls it 5 m across the road? 2.5 m/s 3.2 m/s 6.0 m/s 2.0 m/s 2.8 m/s Previous Answers Correct
2.5 m/s
Max is pushing on the edge (2.4 m from the center) of the merry-go-round to make it rotate. Maya is riding on the merry-go-round, sitting 1.2 m from the center. If Max increases the merry-go-round's angular speed from 0.52 rev/s to 1.5 rev/s in 2.2 s, what is the merry-go-round's angular acceleration? 5.8 rad/s2 3.4 rad/s2 6.7 rad/s2 0.45 rad/s2 2.8 rad/s2
2.8 rad/s^2
You are riding on a roller coaster that starts from rest at a height of 25.0 m and moves down a frictionless track to a height of 3.00 m. How fast are you moving when you arrive at the 3.00-m height? The figure shows a path of a car on a roller coaster. The path starts at the highest point of the coaster, A, 25.0 meters above the ground, then goes downwards and to the right to the point 3.00 meters above the ground, then goes upwards and to the right, reaches the second highest point, then goes downwards and to the right, reaches the ground, passes a circular loop and goes horizontally rightwards. The highest point of the loop, B, is 12.0 meters above the ground. The second highest point is 4.00 meters above the point B. 22.1 m/s 23.4 m/s 20.8 m/s 14.7 m/s
20.8 m/s
A 1000-kg car is moving at a constant speed around a circular turn with a radius of 18.5 meters. How fast must the car move to have an acceleration of 25.2 m/s2? 466 m/s 1.18 m/s 34.3 m/s 21.6 m/s
21.6 m/s
A 3.6-kg chihuahua charges at a speed of 3.3m/s. What is the magnitude of the average force needed to bring the chihuahua to a stop in 0.50s? Express your answer to two significant figures.
24N
On a snowy day, Max (mass = 15 kg) pulls his little sister Maya in a sled (combined mass = 20 kg) through the slippery snow. When Max pulls on the sled with 12 N of force, directed at an angle of 15° above the ground, how much work does Max do on the sled as he pulls his sister 25 m in the snow? 300 J 290 J 11.6 J 77.6 J
290J
A 1000-kg car is moving around a circular turn with a radius of 18.5 meters and decreasing in speed at a rate of 35.2 m/s2. At the instant the car is moving at 16.8 m/s, what is the car's total acceleration? 19.9 m/s2 50.5 m/s2 15.3 m/s2 35.2 m/s2 38.4 m/s2
38.4 m/s^2
On a snowy day, Max (mass = 15 kg) pulls his little sister Maya in a sled (combined mass = 20 kg) through the slippery snow. Max pulls on the sled with 12 N of force, directed at an angle of 15° above the ground. When he comes to a recently plowed section of road, he continues to pull the sled with the same force across the road while the road exerts a frictional force of 4 N on sled. What is the net work done on the sled while Max pulls it 5 m across the road? 38 J 58 J 7.6 J 78 J 16 J
38J
A 1700kg rhino charges at a speed of 50.0km/h. What is the magnitude of the average force needed to bring the rhino to a stop in 0.50s? Express your answer to two significant figures.
4.7×10^4 N
You are riding on a roller coaster that starts from rest at a height of 25.0 m and moves along a frictionless track. However, after a bad storm some leaves settled on part of the track causing a 9.4-m length of the track to exert a frictional force of 625 N on the car. To safely make it around the loop, the 50-kg car must have a minimum speed of 7.7 m/s at the top of the loop (point B). How fast should the car be moving initially at point A to ensure that it reaches the top of the loop with the minimum required speed? The figure shows a path of a car on a roller coaster. The path starts at the highest point of the coaster, A, 25.0 meters above the ground, then goes downwards and to the right to the point 3.00 meters above the ground, then goes upwards and to the right, reaches the second highest point, then goes downwards and to the right, reaches the ground, passes a circular loop and goes horizontally rightwards. The highest point of the loop, B, is 12.0 meters above the ground. The second highest point is 4.00 meters above the point B. 28.0 m/s 17.7 m/s 107 m/s 6.28 m/s 8.90 m/s
6.28 m/s
Max (15 kg) and Maya (12 kg) are riding on a merry-go-round that rotates at a constant speed. Max is sitting on the edge of the merry-go-round, 2.4 m from the center, and Maya is 1.2 m from the center. The merry-go-round is a solid disk with a radius of 2.4 m and a mass of 230 kg. What is the moment of inertia of Max, Maya, and the merry-go-round? 766 kg•m2 1430 kg•m2 104 kg•m2 662 kg•m2 214 kg•m2
766 kg•m2
Cheryl is riding on the edge of a merry-go-round, 2m from the center, which is rotating with an increasing angular speed. Cheryl's tangential acceleration is 3.0m/s2. At the instant that Cheryl's linear speed is 4.0m/s, what is Cheryl's total acceleration?
8.5 m/s^2
Which of the following statements is/are true? Check all that apply. A potential energy function can be specified for a conservative force. The work done by a conservative force depends on the path taken. A potential energy function can be specified for a nonconservative force. A conservative force permits a two-way conversion between kinetic and potential energies. A nonconservative force permits a two-way conversion between kinetic and potential energies. The work done by a nonconservative force depends on the path taken.
A potential energy function can be specified for a conservative force. A conservative force permits a two-way conversion between kinetic and potential energies. The work done by a nonconservative force depends on the path taken.
in the opening scenes of the prelecture video, we outlined some of the key properties of momentum. Which of the following statements are consistent with these properties? Check all that apply. An object's momentum is equal to the product of its mass and its velocity. Momentum is a vector quantity. Momentum is a scalar quantity. An object's momentum is equal to its mass divided by its velocity.
An object's momentum is equal to the product of its mass and its velocity. Momentum is a vector quantity.
A girl and a boy are riding on a merry-go-round that is turning at a constant rate. The girl is near the outer edge, and the boy is closer to the center. Who has greater angular displacement? Both the girl and the boy have zero angular displacement. The girl has greater angular displacement. Both the girl and the boy have the same nonzero angular displacement. The boy has greater angular displacement.
Both the girl and the boy have the same nonzero angular displacement.
A girl and a boy are riding on a merry-go-round that is turning at a constant rate. The girl is near the outer edge, and the boy is closer to the center. Who has greater tangential acceleration? Both the girl and the boy have zero tangential acceleration. The boy has greater tangential acceleration. Both the girl and the boy have the same nonzero tangential acceleration. The girl has greater tangential acceleration.
Both the girl and the boy have zero tangential acceleration.
A girl spins around in a circle trying to make herself dizzy. Without changing her position, she starts spinning twice as fast. By how much did her rotational kinetic energy change? It halved. It quadrupled. It doubled. It did not change.
It quadrupled.
Suppose our experimenter repeats his experiment on a planet more massive than Earth, where the acceleration due to gravity is g=30 m/s2. When he releases the ball from chin height without giving it a push, how will the ball's behavior differ from its behavior on Earth? Ignore friction and air resistance. (Select all that apply.) View Available Hint(s) It will smash his face. Its mass will be greater. It will take more time to return to the point from which it was released. It will stop well short of his face. It will take less time to return to the point from which it was released.
It will take less time to return to the point from which it was released.
For an INELASTIC collision, which of the following statements are true? Choose all that apply. Kinetic energy is lost. Kinetic energy is conserved. Momentum is gained. Momentum is lost. Kinetic energy is gained. Momentum is conserved.
Kinetic energy is lost. Momentum is conserved.
Which of the following statements is/are true? Check all that apply. The total mechanical energy of a system, at any one instant, is either all kinetic or all potential energy. Mechanical energy can be dissipated to nonmechanical forms of energy. The total mechanical energy of a system is equally divided between kinetic and potential energy. The total mechanical energy of a system is constant only if nonconservative forces do work. The total mechanical energy of a system is constant only if conservative forces do work.
Mechanical energy can be dissipated to nonmechanical forms of energy. The total mechanical energy of a system is constant only if conservative forces do work.
For an elastic collision, which of the following statements are true? Choose all that apply. Momentum is lost. Momentum is gained. Kinetic energy is lost. Momentum is conserved. Kinetic energy is conserved. Kinetic energy is gained.
Momentum is conserved. Kinetic energy is conserved.
Person B does twice the work of person A, and in one-half of the time . How does the power output of person B compare to person A? Person B has the same power output as person A. Person B has four times the power output of person A. Person B has half the power output of person A. Person B has eight times the power output of person A. Person B has twice the power output of person A.
Person B has four times the power output of person A.
Which of the following statements is/are true? Check all that apply. The SI unit of power is the horsepower. Power is the rate at which energy is transformed. Power is the rate at which work is done. The SI unit of power is the watt. A person is limited in the total work he or she can do by their power output.
Power is the rate at which energy is transformed. Power is the rate at which work is done. The SI unit of power is the watt.
Bumper cars A and B undergo a collision during which the momentum of the combined system is conserved. Which equation(s) correctly states the principle of conservation of momentum? Check all that apply. P⃗ A,i+P⃗ B,i=P⃗ A,f+P⃗ B,f P⃗ A,i+P⃗ A,f=P⃗ B,i+P⃗ B,f ΔP⃗ A=ΔP⃗ B ΔP⃗ A+ΔP⃗ B=0
P⃗ A,i+P⃗ B,i=P⃗ A,f+P⃗ B,f ΔP⃗ A+ΔP⃗ B=0
The video shows an animated billiards experiment in which a cue ball strikes a glued-in-place eight-ball. Which of the following explains why the momentum of the eight-ball is conserved? The eight-ball is an isolated system. The "glue force" cancels the collision force. The collision is elastic. The cue ball rebounds with the same speed it had coming in.
The "glue force" cancels the collision force.
A lump of putty and a rubber ball have equal mass. Both are thrown with equal speed against a wall. The putty sticks to the wall. The ball bounces back at nearly the same speed with which it hit the wall. Which object experiences the greater momentum change? The putty experiences the greater momentum change. The ball experiences the greater momentum change. They both experience the same momentum change. Not enough information is given to determine the answer.
The ball experiences the greater momentum change.
When a constant force acts on an object, what does the object's change in momentum depend upon? Check all that apply. The change in momentum depends upon the magnitude of the force. The change in momentum depends upon the change in the velocity of the object. The change in momentum depends upon the time interval during which the force acts. The change in momentum depends upon the change in the position of the object. The change in momentum depends upon the mass of the object.
The change in momentum depends upon the magnitude of the force. The change in momentum depends upon the change in the velocity of the object. The change in momentum depends upon the time interval during which the force acts. The change in momentum depends upon the mass of the object.
A girl and a boy are riding on a merry-go-round that is turning at a constant rate. The girl is near the outer edge, and the boy is closer to the center. Who has greater linear speed? The girl has greater linear speed. Both the girl and the boy have zero linear speed. Both the girl and the boy have the same nonzero linear speed. The boy has greater linear speed.
The girl has greater linear speed.
What represents the impulse of the force in a graph of force versus time? The impulse is equal to the product of the maximum force times the maximum time. The impulse is equal to the area under the curve. The impulse is equal to length of the curve. The impulse is equal to the slope of the curve. Impulse cannot be determined from this type of graph.
The impulse is equal to the area under the curve.
In a lab environment, you are investigating the impulse of a force exerted on a brick when the brick's speed is reduced from 2.5 m/s to a complete stop. First, you allow the brick to slam into a secured piece of wood, bringing the brick to a sudden stop. Second, you allow the brick to plow into a large slab of gelatin so that the brick comes to a gradual halt. In which situation is there a greater impulse of the force on the brick? There is a greater impulse of the force on the brick from the gelatin. Not enough information is given to determine the answer. The impulse is the same in both situations. There is a greater impulse of the force on the brick from the wall.
The impulse is the same in both situations.
Two identical balls are thrown vertically upward. The second ball is thrown with an initial speed that is twice that of the first ball. How does the maximum height of the two balls compare? The maximum height of the second ball is four times that of the first ball. The maximum height of the second ball is eight times that of the first ball. The maximum height of the second ball is 1.41 times that of the first ball. The maximum height of the second ball is two times that of the first ball. The maximum heights of the two balls are equal.
The maximum height of the second ball is four times that of the first ball.
Which statement must be true for the momentum of a system to be conserved? The net external force on the system is zero. The internal forces sum to zero. The net external force on the system is non-zero. There are no external forces acting on the system.
The net external force on the system is zero.
A person applies a 50 N force on a crate, causing it to move horizontally at a constant speed through a distance of 10 m. What is the net work done on the crate? The net work done on the crate is zero joules. The net work done on the crate is 0.2 J. The net work done on the crate is 5 J. The net work done on the crate is 500 J. The net work done on the crate is 250 J.
The net work done on the crate is zero joules.
If the net work done on an object is positive, what can you conclude about the object's motion? The object is speeding up. The object is at rest; its position is constant. The object is slowing down. The object is moving with a constant velocity.
The object is speeding up.
If the net work done on an object is zero, what can you determine about the object's kinetic energy? The object's kinetic energy is increasing. The object's kinetic energy is zero. The object's kinetic energy remains the same. The object's kinetic energy is decreasing.
The object's kinetic energy remains the same.
While goofing off at the ice skating rink, a student takes off her shoes and places each of them on the ice. Her friend, a hockey player, then shoots a hockey puck at each shoe. The first puck immediately comes to rest after it collides with the left shoe. The second puck rebounds after it collides with the right shoe. If each hockey puck has the same incoming speed, which shoe has greater speed after the collision? Both shoes have the same speed. The right shoe The left shoe
The right shoe
A freight car moves along a frictionless level railroad track at constant speed. The freight car is open on the top. A large load of sand is suddenly dumped into the freight car. What happens to the speed of the freight car? The speed of the freight car increases. The speed of the freight car remains the same. The speed of the freight car cannot be determined from the information given. The speed of the freight car decreases.
The speed of the freight car decreases.
Which of the following statements are true? Select all correct responses. Choose all that apply. The total momentum of any system is constant. The total momentum of any number of particles is equal to the vector sum of the momenta of the individual particles. The total momentum of an isolated system is constant. The total momentum of any number of particles is equal to the algebraic sum of the momenta of the individual particles. The vector sum of forces acting on a particle equals the rate of change of momentum of the particle with respect to time. The vector sum of forces acting on a particle equals the rate of change of velocity of the particle with respect to time.
The total momentum of any number of particles is equal to the vector sum of the momenta of the individual particles. The total momentum of an isolated system is constant. The vector sum of forces acting on a particle equals the rate of change of momentum of the particle with respect to time
When a person steps forward out of a small boat onto a dock, the boat recoils backward in the water. Why does this occur? The total mechanical energy of the system is conserved. The total momentum of the system is conserved. The momentum of the boat is greater than the momentum of the person. The energy of the boat is greater than the energy of the person. The energy of the person is greater than the energy of the boat. The momentum of the person is greater than the momentum of the boat.
The total momentum of the system is conserved.
Two objects are moving at equal speed along a level, frictionless surface. The second object has twice the mass of the first object. They both slide up the same frictionless incline plane. Which object rises to a greater height? Object 2 rises to the greater height because it contains more mass. Object 1 rises to the greater height because it weighs less. Object 2 rises to the greater height because it possesses a larger amount of kinetic energy. Object 1 rises to the greater height because it possesses a smaller amount of kinetic energy. The two objects rise to the same height.
The two objects rise to the same height.
A red ball with a velocity of +3.0 m/s collides head-on with a yellow ball of equal mass moving with a velocity of −2.0 m/s. What is the velocity of the two balls after the elastic collision? The velocity of the red ball is +3.0 m/s; the velocity of the yellow ball is −2.0 m/s. The yellow ball stops immediately, and the red ball has a velocity of −1 m/s. The velocity of the red ball is −3.0 m/s; the velocity of the yellow ball is +2.0 m/s. The red ball stops immediately, and the yellow ball has a velocity of +1 m/s. The velocity of the red ball is +2.0 m/s; the velocity of the yellow ball is −3.0 m/s. The velocity of the red ball is −2.0 m/s; the velocity of the yellow ball is +3.0 m/s.
The velocity of the red ball is −2.0 m/s; the velocity of the yellow ball is +3.0 m/s.
A graph depicts force versus position. What represents the work done by the force over the given displacement? The work done is equal to length of the curve. The work done is equal to the area under the curve. The work done is equal to the product of the maximum force times the maximum position. The work done is equal to the slope of the curve. Work cannot be determined from this type of graph.
The work done is equal to the area under the curve.
An object weighing 20 N moves horizontally toward the right a distance of 5.0 m. What is the work done on the object by the force of gravity? The work done on the object by the force of gravity is 100 J. The work done on the object by the force of gravity is 50 J. The work done on the object by the force of gravity is 4.0 J. The work done on the object by the force of gravity is zero joules. The work done on the object by the force of gravity is 0.25 J.
The work done on the object by the force of gravity is zero joules
Which turbine takes the lesser amount of time to rotate through 1.0 radian of angular displacement? turbine A turbine B They take the same amount of time. The answer cannot be determined from the information given.
They take the same amount of time.
As in Part D, two wind turbines with different length blades are rotating. Consider what needs to happen in order to change the angular speed of one of the turbines. If the turbine is to spin more quickly, should the angular acceleration, α⃗ be positive or negative? α⃗ should be positive. α⃗ should be negative. We cannot tell which direction α⃗ should be without knowing the direction of the angular velocity, ω⃗ .
We cannot tell which direction α⃗ should be without knowing the direction of the angular velocity, ω⃗ .
A ball is thrown straight upward. How does the sign of the work done by gravity while the ball is traveling upward compare with the sign of the work done by gravity while the ball is traveling downward? Work done by gravity is positive while the ball is traveling both upward and downward. Work done by gravity is positive while the ball is traveling upward and negative while the ball is traveling downward. Work done by gravity is negative while the ball is traveling both upward and downward. Work done by gravity is negative while the ball is traveling upward and positive while the ball is traveling downward.
Work done by gravity is negative while the ball is traveling upward and positive while the ball is traveling downward.
Rather than ascribing the increased kinetic energy of the stone to the work of gravity, we now (when using potential energy rather than work-energy) say that the increased kinetic energy comes from the ______ of the _______ energy. Choose the best answer to fill in the blanks above: work / potential force / kinetic change / potential
change / potential
The work-energy theorem states that a force acting on a particle as it moves over a ______ changes the ______ energy of the particle if the force has a component parallel to the motion. Choose the best answer to fill in the blanks above: distance / potential distance / kinetic vertical displacement / potential none of the above
distance / kinetic
To illustrate the work-energy concept, consider the case of a stone falling from xi to xf under the influence of gravity. Using the work-energy concept, we say that work is done by the gravitational _____, resulting in an increase of the ______ energy of the stone. Choose the best answer to fill in the blanks above: force / kinetic potential energy / potential force / potential potential energy / kinetic
force / kinetic
Two racecars are driving at constant speeds around a circular track. Both cars are the same distance away from the center of the track, but car 2 is driving twice as fast as car 1. The acceleration of car 2 is ___________ the acceleration of car 1. a quarter of twice half of equal to four times
four times
If the larger wheel in (Figure 1) rotates with angular speed ωB, what can you say about the angular speed of the smaller wheel? The angular speed of the smaller wheel is _______ ωB.
greater than
Two children are riding on a merry-go-round that is rotating with a constant angular speed. Abbie is one meter from the center of the merry-go-round, whereas Zak is two meters from the center. Abbie's acceleration is ___________ Zak's acceleration. equal to a quarter of four times half of twice
half of
A motorcycle drives up a steeply inclined ramp. The work done on the motorcycle by the Earth's gravitational force is ____. positive zero negative
negative
To calculate the change in kinetic energy, you must know the force as a function of _______. The work done by the force causes the kinetic energy change. Choose the best answer to fill in the blank above: acceleration work position potential energy
position
If the larger wheel in (Figure 1) turns clockwise, is the angular velocity of the smaller wheel positive or negative using the convention described in the video? positive negative
positive
This process happens in such a way that total mechanical energy, equal to the ______ of the kinetic and potential energies, is _______. Choose the best answer to fill in the blanks above: sum / conserved sum / zero sum / not conserved difference / conserved
sum / conserved
During a certain time interval, the net work done on an object is zero joules. We can be certain that ____. the object was at rest at the end of this interval the object was at rest during this entire interval the object's final speed was the same as its initial speed
the object's final speed was the same as its initial speed
Two identical cars are driving in opposite directions at the same speed. Their kinetic energies have ____. the same magnitude and sign the same magnitude, but opposite signs different magnitudes and opposite signs different magnitudes, but the same sign
the same magnitude and sign
A solid sphere and a hollow sphere (spherical shell) of the same mass and same radius rotate with the same amount of kinetic energy. Which one is rotating faster? the solid sphere the hollow sphere Neither; they must be rotating at the same speed.
the solid sphere