Halliday/Resnick/Walker Fundamentals of Physics 8th edition Classroom Response System Questions Chapter 11 Rolling, Torque, and Angular Momentum Reading Quiz Questions

11.2.1. A wheel is rolling without slipping along a straight, level road. Which one of the following statements concerning the speed of the center of the wheel is true? a) A point on the rim is moving at a tangential speed that is equal to the speed at the center of the wheel. b) A point on the rim is moving at a tangential speed that is one-half the speed at the center of the wheel. c) A point on the rim is moving at a tangential speed that is two times the speed at the center of the wheel. d) A point on the rim moves at a speed that is not related to the speed at the center of the wheel. e) A point on the rim is moving at a tangential speed that varies as the wheel rotates, but the speed at the center of the wheel is constant.

11.2.1. A wheel is rolling without slipping along a straight, level road. Which one of the following statements concerning the speed of the center of the wheel is true? a) A point on the rim is moving at a tangential speed that is equal to the speed at the center of the wheel. b) A point on the rim is moving at a tangential speed that is one-half the speed at the center of the wheel. c) A point on the rim is moving at a tangential speed that is two times the speed at the center of the wheel. d) A point on the rim moves at a speed that is not related to the speed at the center of the wheel. e) A point on the rim is moving at a tangential speed that varies as the wheel rotates, but the speed at the center of the wheel is constant.

11.2.2. The wheels of a NASCAR racer roll without slipping as the car moves in a circular path at constant speed. Which one of the following quantities has a non-zero value and has a constant value in this situation? a) linear velocity b) centripetal acceleration c) angular velocity d) angular acceleration e) total acceleration

11.2.2. The wheels of a NASCAR racer roll without slipping as the car moves in a circular path at constant speed. Which one of the following quantities has a non-zero value and has a constant value in this situation? a) linear velocity b) centripetal acceleration c) angular velocity d) angular acceleration e) total acceleration

11. 2. 3. At the post office, a customer has dropped a coin 11.2.3. At the post office, a customer has dropped a coin. The coin is rolling on its side across the floor. Which one of the following statements concerning this situation is true? a) The tangential velocity is the same for all points on the side of the coin. b) There is no slipping at the point where the coin touches the floor. c) The angular acceleration of the coin must be zero m/s2. d) The tangential velocity is the same for all points on the coin. e) The linear velocity for all points on the coin is non-zero.

11. 2. 3. At the post office, a customer has dropped a coin 11.2.3. At the post office, a customer has dropped a coin. The coin is rolling on its side across the floor. Which one of the following statements concerning this situation is true? a) The tangential velocity is the same for all points on the side of the coin. b) There is no slipping at the point where the coin touches the floor. c) The angular acceleration of the coin must be zero m/s2. d) The tangential velocity is the same for all points on the coin. e) The linear velocity for all points on the coin is non-zero.

11.3.1. Consider the following kinds of energy: (1) translational, (2) rotational, (3) elastic potential energy, and (4) gravitational potential energy. Which of these kinds of energy are involved when a wheel rolls without slipping along a flat, horizontal surface? a) 1, 2, 3, and 4 b) 1, 2, and 4 only c) 1 and 2 only d) 1 only e) 2 only

11.3.1. Consider the following kinds of energy: (1) translational, (2) rotational, (3) elastic potential energy, and (4) gravitational potential energy. Which of these kinds of energy are involved when a wheel rolls without slipping along a flat, horizontal surface? a) 1, 2, 3, and 4 b) 1, 2, and 4 only c) 1 and 2 only d) 1 only e) 2 only

11.3.2. An object is rolling, so its motion involves both rotation and translation. Which one of the following statements must be true concerning this situation? a) The total mechanical energy is equal to the sum of the translational and rotational kinetic energies and the gravitational potential energy of the object. b) The translational kinetic energy may be equal to zero joules. c) The gravitational potential energy must be changing as the object rolls. d) The rotational kinetic energy must be constant as the object rolls. e) The total mechanical energy is equal to the sum of the translational kinetic energy and the gravitational potential energy of the object.

11.3.2. An object is rolling, so its motion involves both rotation and translation. Which one of the following statements must be true concerning this situation? a) The total mechanical energy is equal to the sum of the translational and rotational kinetic energies and the gravitational potential energy of the object. b) The translational kinetic energy may be equal to zero joules. c) The gravitational potential energy must be changing as the object rolls. d) The rotational kinetic energy must be constant as the object rolls. e) The total mechanical energy is equal to the sum of the translational kinetic energy and the gravitational potential energy of the object.

11.3.3. Consider the drawing of a wheel that is rolling toward to the right and in constant contact with the ground below. When considering the kinetic energy of rolling, the rolling is about an axis that passes through which of the points indicated? a) A b) B c) C d) D e) E

11.3.3. Consider the drawing of a wheel that is rolling toward to the right and in constant contact with the ground below. When considering the kinetic energy of rolling, the rolling is about an axis that passes through which of the points indicated? a) A b) B c) C d) D e) E

11.3.4. Consider the drawing of a wheel that is rolling toward to the right and in constant contact with the ground below. At which of the points indicated is the magnitude of the linear velocity the greatest? a) A b) B c) C d) D e) E

11.3.4. Consider the drawing of a wheel that is rolling toward to the right and in constant contact with the ground below. At which of the points indicated is the magnitude of the linear velocity the greatest? a) A b) B c) C d) D e) E

11. 3. 5. A solid cylinder is rolling along a flat, horizontal plane 11.3.5. A solid cylinder is rolling along a flat, horizontal plane. The center of mass of the cylinder is moving toward the south at constant velocity. Which one of the following statements concerning the translational and rotational kinetic energies of the cylinder is true? a) The translational kinetic energy is greater than the rotational kinetic energy. b) The translational kinetic energy is less than the rotational kinetic energy. c) The translational kinetic energy is equal to the rotational kinetic energy. d) The sum of the translational and rotational kinetic energies equals the gravitational potential energy of the cylinder. e) The sum of the translational and rotational kinetic energies equals zero joules.

11. 3. 5. A solid cylinder is rolling along a flat, horizontal plane 11.3.5. A solid cylinder is rolling along a flat, horizontal plane. The center of mass of the cylinder is moving toward the south at constant velocity. Which one of the following statements concerning the translational and rotational kinetic energies of the cylinder is true? a) The translational kinetic energy is greater than the rotational kinetic energy. b) The translational kinetic energy is less than the rotational kinetic energy. c) The translational kinetic energy is equal to the rotational kinetic energy. d) The sum of the translational and rotational kinetic energies equals the gravitational potential energy of the cylinder. e) The sum of the translational and rotational kinetic energies equals zero joules.

11. 4. 1. Cylinders A and B are identical 11.4.1. Cylinders A and B are identical. Cylinder A is allowed to roll down a ramp without slipping. Cylinder B is allowed to slide down a similar ramp that has the same incline angle, but it is frictionless. Which one of the following statements concerning this situation, assuming the cylinders begin from rest at the same height, is true? a) The sum of the translational and rotational kinetic energies of cylinder A is smaller than the translational kinetic energy of cylinder B. b) The sum of the translational and rotational kinetic energies of cylinder A is equal to the translational kinetic energy of cylinder B. c) The sum of the translational and rotational kinetic energies of cylinder A is larger than the translational kinetic energy of cylinder B.

11. 4. 1. Cylinders A and B are identical 11.4.1. Cylinders A and B are identical. Cylinder A is allowed to roll down a ramp without slipping. Cylinder B is allowed to slide down a similar ramp that has the same incline angle, but it is frictionless. Which one of the following statements concerning this situation, assuming the cylinders begin from rest at the same height, is true? a) The sum of the translational and rotational kinetic energies of cylinder A is smaller than the translational kinetic energy of cylinder B. b) The sum of the translational and rotational kinetic energies of cylinder A is equal to the translational kinetic energy of cylinder B. c) The sum of the translational and rotational kinetic energies of cylinder A is larger than the translational kinetic energy of cylinder B.

11. 4. 2. A solid cylinder is freely rolling down an inclined plane 11.4.2. A solid cylinder is freely rolling down an inclined plane. What is the direction of the friction force acting on the cylinder and at what point does the friction force act? a) The friction force acts at the center of mass of the cylinder and is directed up the plane. b) The friction force acts at the center of mass of the cylinder and is directed down the plane. c) The friction force acts at the point of contact between the cylinder and the plane and is directed up the plane. d) The friction force acts at the point of contact between the cylinder and the plane and is directed down the plane. e) The friction force acts at the point of contact between the cylinder and the plane and is directed perpendicular to the plane, in the direction opposite to the normal force.

11. 4. 2. A solid cylinder is freely rolling down an inclined plane 11.4.2. A solid cylinder is freely rolling down an inclined plane. What is the direction of the friction force acting on the cylinder and at what point does the friction force act? a) The friction force acts at the center of mass of the cylinder and is directed up the plane. b) The friction force acts at the center of mass of the cylinder and is directed down the plane. c) The friction force acts at the point of contact between the cylinder and the plane and is directed up the plane. d) The friction force acts at the point of contact between the cylinder and the plane and is directed down the plane. e) The friction force acts at the point of contact between the cylinder and the plane and is directed perpendicular to the plane, in the direction opposite to the normal force.

11.5.1. The text uses which of the following physical situations, or analogies, to find the equation of acceleration for the center of mass of the yo-yo? a) an object rolling down an inclined plane b) a spinning top c) a car drive around a banked curve d) a satellite orbiting the earth e) the blades of a fan rotating at low speed

11.5.1. The text uses which of the following physical situations, or analogies, to find the equation of acceleration for the center of mass of the yo-yo? a) an object rolling down an inclined plane b) a spinning top c) a car drive around a banked curve d) a satellite orbiting the earth e) the blades of a fan rotating at low speed

11.6.1. The entrance door to a video store is pivoted about the hinges on the left side of the door. When you begin to push on the right side of the door to enter the store, what is the direction of the torque on the door? a) into the store b) out of the store c) upward d) clockwise e) counterclockwise

11.6.1. The entrance door to a video store is pivoted about the hinges on the left side of the door. When you begin to push on the right side of the door to enter the store, what is the direction of the torque on the door? a) into the store b) out of the store c) upward d) clockwise e) counterclockwise

11.6.2. An L-shaped bracket with sides of length 2L and L has two forces acting on it, as shown in the drawing. One of the forces has a magnitude F and the other has a magnitude 2F. The bracket is free to rotate about the point P shown. What is the magnitude and direction of the net torque acting on this bracket? a) 1.29LF, into the page/screen b) 0.59LF, into the page/screen c) 1.29LF, out of the page/screen d) 0.59LF, out of the page/screen e) zero

11.6.2. An L-shaped bracket with sides of length 2L and L has two forces acting on it, as shown in the drawing. One of the forces has a magnitude F and the other has a magnitude 2F. The bracket is free to rotate about the point P shown. What is the magnitude and direction of the net torque acting on this bracket? a) 1.29LF, into the page/screen b) 0.59LF, into the page/screen c) 1.29LF, out of the page/screen d) 0.59LF, out of the page/screen e) zero

11.7.1. Which one of the following choices represents the SI units for angular momentum? a) kg  m/s2 b) kg  m2/s c) kg  m2/s d) kg  m  rad/s e) kg  rad/s2

11.7.1. Which one of the following choices represents the SI units for angular momentum? a) kg  m/s2 b) kg  m2/s c) kg  m2/s d) kg  m  rad/s e) kg  rad/s2

11.7.2. A hoop rolls without slipping on a horizontal surface and it moves due east at a constant linear speed. What is the direction of its angular momentum? a) north b) east c) south d) west e) downward

11.7.2. A hoop rolls without slipping on a horizontal surface and it moves due east at a constant linear speed. What is the direction of its angular momentum? a) north b) east c) south d) west e) downward

11.7.3. There is a restaurant on top of a tall, circular building that is designed to rotate about its center at a constant angular speed. Which one of the following quantities is non-zero and constant for one of the restaurant’s customers seated near a window? a) linear velocity b) centripetal acceleration c) angular momentum d) angular acceleration

11.7.3. There is a restaurant on top of a tall, circular building that is designed to rotate about its center at a constant angular speed. Which one of the following quantities is non-zero and constant for one of the restaurant’s customers seated near a window? a) linear velocity b) centripetal acceleration c) angular momentum d) angular acceleration

11.7.4. Three objects, a solid sphere, a hollow ring, and a solid disk, have the same radius R. A string is wrapped around each object and the same tangential force is applied to each object at R and time t = 0 s. Which one of the following statements concerning the angular momentum of these objects after a short time t has elapsed, assuming the tangential force was continually applied? a) The angular momentum of the solid disk is larger than that of the other two objects. b) The angular momentum of the solid sphere is larger than that of the other two objects. c) The angular momentum of the hollow ring is larger than that of the other two objects. d) The angular momentum of all of the objects has the same value. e) The angular momentum of the solid disk and hollow ring are equal, but that of the solid sphere is smaller.

11.7.4. Three objects, a solid sphere, a hollow ring, and a solid disk, have the same radius R. A string is wrapped around each object and the same tangential force is applied to each object at R and time t = 0 s. Which one of the following statements concerning the angular momentum of these objects after a short time t has elapsed, assuming the tangential force was continually applied? a) The angular momentum of the solid disk is larger than that of the other two objects. b) The angular momentum of the solid sphere is larger than that of the other two objects. c) The angular momentum of the hollow ring is larger than that of the other two objects. d) The angular momentum of all of the objects has the same value. e) The angular momentum of the solid disk and hollow ring are equal, but that of the solid sphere is smaller.

11.7.5. Three objects, a solid sphere, a hollow ring, and a solid disk, have the same radius R. A string is wrapped around each object and the same tangential force is applied to each object at R and time t = 0 s. Which one of the following statements concerning the angular velocity of these objects after a short time t has elapsed, assuming the tangential force was continually applied? a) The angular velocity of the solid disk is larger than that of the other two objects. b) The angular velocity of the solid sphere is larger than that of the other two objects. c) The angular velocity of the hollow ring is larger than that of the other two objects. d) The angular velocity of all of the objects has the same value. e) The angular velocity of the solid disk and hollow ring are equal, but that of the solid sphere is smaller.

11.7.5. Three objects, a solid sphere, a hollow ring, and a solid disk, have the same radius R. A string is wrapped around each object and the same tangential force is applied to each object at R and time t = 0 s. Which one of the following statements concerning the angular velocity of these objects after a short time t has elapsed, assuming the tangential force was continually applied? a) The angular velocity of the solid disk is larger than that of the other two objects. b) The angular velocity of the solid sphere is larger than that of the other two objects. c) The angular velocity of the hollow ring is larger than that of the other two objects. d) The angular velocity of all of the objects has the same value. e) The angular velocity of the solid disk and hollow ring are equal, but that of the solid sphere is smaller.

11.8.1. The vector sum of all of the torques acting on a particle is equal to the time rate of change of which on of the following quantities? a) angular momentum b) angular acceleration c) net force d) moment of inertia e) rotational kinetic energy

11.8.1. The vector sum of all of the torques acting on a particle is equal to the time rate of change of which on of the following quantities? a) angular momentum b) angular acceleration c) net force d) moment of inertia e) rotational kinetic energy

11. 9. 1. Consider a system of particles 11.9.1. Consider a system of particles. Which one of the following statements concerning the choice of the origin for this system is true? a) The origin may be chosen to be anywhere in the universe. b) The origin must be located at the center of mass of one of the particles that compose the system. c) The origin must always be located at the center of mass of the particle system. d) The origin must be at the center of mass of the system of particles if the center of mass is accelerating. e) The origin must be at the center of mass of the system of particles if the center of mass is moving at constant velocity.

11. 9. 1. Consider a system of particles 11.9.1. Consider a system of particles. Which one of the following statements concerning the choice of the origin for this system is true? a) The origin may be chosen to be anywhere in the universe. b) The origin must be located at the center of mass of one of the particles that compose the system. c) The origin must always be located at the center of mass of the particle system. d) The origin must be at the center of mass of the system of particles if the center of mass is accelerating. e) The origin must be at the center of mass of the system of particles if the center of mass is moving at constant velocity.

11.10.1. Which one of the following expressions allows one to calculate the angular momentum for a rigid body about a fixed axis? a) (1/2) I2 b) (1/2) MR2 c) 2I d) I e) (1/2) MRv2

11.10.1. Which one of the following expressions allows one to calculate the angular momentum for a rigid body about a fixed axis? a) (1/2) I2 b) (1/2) MR2 c) 2I d) I e) (1/2) MRv2

11.11.1. A child standing on the edge of a freely spinning merry-go-round moves quickly to the center. Which one of the following statements is necessarily true concerning this event and why? a) The angular speed of the system decreases because the moment of inertia of the system has decreased. b) The angular speed of the system increases because the moment of inertia of the system has decreased. c) The angular speed of the system increases because the moment of inertia of the system has increased. d) The angular speed of the system decreases because the moment of inertia of the system has increased. e) The angular speed of the system remains the same because the net torque on the merry-go-round is zero N  m.

11.11.1. A child standing on the edge of a freely spinning merry-go-round moves quickly to the center. Which one of the following statements is necessarily true concerning this event and why? a) The angular speed of the system decreases because the moment of inertia of the system has decreased. b) The angular speed of the system increases because the moment of inertia of the system has decreased. c) The angular speed of the system increases because the moment of inertia of the system has increased. d) The angular speed of the system decreases because the moment of inertia of the system has increased. e) The angular speed of the system remains the same because the net torque on the merry-go-round is zero N  m.

11.11.2. What happens when a spinning ice skater draws in her outstretched arms? a) Her moment of inertia decreases causing her to slow down. b) Her angular momentum decreases. c) The torque that she exerts increases her moment of inertia. d) Her angular momentum increases. e) Her moment of inertia decreases causing her to speed up.

11.11.2. What happens when a spinning ice skater draws in her outstretched arms? a) Her moment of inertia decreases causing her to slow down. b) Her angular momentum decreases. c) The torque that she exerts increases her moment of inertia. d) Her angular momentum increases. e) Her moment of inertia decreases causing her to speed up.

11.11.3. A ball moves in a circular path on a horizontal, frictionless surface as shown. It is attached to a light string that passes through a hole in the center of the table. If the string is pulled down, thereby reducing the radius of the path of the ball, the speed of the ball is observed to increase. Which one of the following statements provides an explanation for this increase? a) When the string is pulled downward, the angular momentum must increase. b) The total mechanical energy of the ball must remain constant because energy is conserved. c) The angular momentum of the ball is conserved in this process. d) The linear momentum of the ball is conserved in this process. e) This follows from applying Newton’s third law of motion.

11.11.3. A ball moves in a circular path on a horizontal, frictionless surface as shown. It is attached to a light string that passes through a hole in the center of the table. If the string is pulled down, thereby reducing the radius of the path of the ball, the speed of the ball is observed to increase. Which one of the following statements provides an explanation for this increase? a) When the string is pulled downward, the angular momentum must increase. b) The total mechanical energy of the ball must remain constant because energy is conserved. c) The angular momentum of the ball is conserved in this process. d) The linear momentum of the ball is conserved in this process. e) This follows from applying Newton’s third law of motion.

11. 11. 4. At the carnival, a child is riding on a carousel 11.11.4. At the carnival, a child is riding on a carousel. She has chosen to ride one of the animals near the outer rim, a Siberian tiger, even though it does move up and down. As the carousel is turning her bracelet falls from her wrist, even though her hand was firmly gripping a handle near the tiger’s ear. Which of the following quantities for the bracelet is conserved as it falls? a) angular momentum only b) rotational kinetic energy only c) total mechanical energy only d) angular momentum and mechanical energy e) None of the above choices are correct.

11. 11. 4. At the carnival, a child is riding on a carousel 11.11.4. At the carnival, a child is riding on a carousel. She has chosen to ride one of the animals near the outer rim, a Siberian tiger, even though it does move up and down. As the carousel is turning her bracelet falls from her wrist, even though her hand was firmly gripping a handle near the tiger’s ear. Which of the following quantities for the bracelet is conserved as it falls? a) angular momentum only b) rotational kinetic energy only c) total mechanical energy only d) angular momentum and mechanical energy e) None of the above choices are correct.