Energy Review

1. A block of mass m is pulled over a distance d by an applied force F which is directed in parallel to the displacement. How much work is done on the block by the force F?

• mFd

• zero

• Fd

• –Fd

1. A block of mass m is moved over a distance d. An applied force F is directed perpendicularly to the block’s displacement. How much work is done on the block by the force F?

• mFd

• zero

• Fd

• –Fd

1. A block of mass m is moved over a distance d. An applied force F is opposite to the block’s displacement. How much work is done on the block by the force F?

• mFd

• zero

• Fd

• –Fd

1. A truck driver is trying to push a loaded truck with an applied force. Unfortunately, his attempt was unsuccessful the truck stays stationary no matter how hard the driver pushes. How much work is done by the driver?

• Fd

• –Fd

• Zero

A container with a mass of 5 kg is lifted to a height of 8 m. How much work is done by the gravitational force?

• 400 J

• -400 J

• C. zero

• D. 50 J

1. A container with a mass of 5 kg is lifted to a height of 8 m. How much work is done by the external force?

• A. 400 J

• B. -400 J

• C. zero

• D. 50 J

1. An applied force F accelerates an object from rest to a velocity v. How much work is done by the applied force F?

• A. ½ mv²

• B. mgh

• C. ½ kx²

• D. mFd

1. What happens to the kinetic energy of a moving object if the net work done is positive?

• A. The kinetic energy increases

• B. The kinetic energy decreases

• C. The kinetic energy remains the same

• D. The kinetic energy is zero

1. What happens to the gravitational potential energy of a moving object if the work done by the gravitational force is negative?

• A. The potential energy increases

• B. The potential energy decreases

• C. The potential energy remains the same

• D. The potential energy is zero

1. An object I with a mass of 4 kg is lifted vertically 3 m from the ground level; another object II with a mass of 2 kg is lifted 6 m up. Which of the following statements is true?

I. Object I has greater potential energy since it is heavier

II. Object II has greater potential energy since it is lifted to a higher position

III. Two objects have the same potential energy

• A. I

• B. II

• C. III

• D. II and III