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A truck loaded with sand accelerates along a highway. The driving force on the truck remains constant. What happens to the acceleration of the truck as its trailer leaks sand at a constant rate throug

A. It decreases at a steady rate
B. It increases at a steady rate
C. It increases and then decreases
D. It decreases and then increases
E. It remains constant
F. None of these

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A large crate of mass m is placed on the back of a truck but not tied down. As the truck accelerates forward with an acceleration a, the crate remains at rest relative to the truck. What force causes

A. the normal force
B. the force of gravity
C. the force of friction between the crate and the floor of the truck
D. the “ma” force
E. none of these

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An object that’s moving with constant speed travels once around a circular path. Which of the following is/are true concerning this motion？I. The displacement is zero. II. The average speed is zero. I

A. I only
B. I and II only
C. I and III only
D. III only
E. II and III only

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As a block slides down a frictionless incline, which of the following statements is true（）

A. Both its speed and acceleration increase
B. Its speed and acceleration remain constant
C. Its speed increases and its acceleration remains constant
D. Both its speed and acceleration decrease
E. Its speed increases and its acceleration decreases
F. None of these

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Which of the following is an example of a nonconservative force（）

A. gravity
B. magnetism
C. friction
D. none of the others

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A truck loaded with sand accelerates along a highway. The driving force on the truck remains constant. What happens to the acceleration of the truck as its trailer leaks sand at a constant rate throug

A. It decreases at a steady rate B. It increases at a steady rate C. It increases and then decreases D. It decreases and then increases E. It remains constant F. None of these

A large crate of mass m is placed on the back of a truck but not tied down. As the truck accelerates forward with an acceleration a, the crate remains at rest relative to the truck. What force causes

An object that’s moving with constant speed travels once around a circular path. Which of the following is/are true concerning this motion？I. The displacement is zero. II. The average speed is zero. I

As a block slides down a frictionless incline, which of the following statements is true（）

Which of the following is an example of a nonconservative force（）

A. It decreases at a steady rate
B. It increases at a steady rate
C. It increases and then decreases
D. It decreases and then increases
E. It remains constant
F. None of these