Exam 4 Physics Numbers 11-15 2016-2017

1. 15. Which of the following is evidence that frictional forces are present in a system?

A. Interactions in the system cause an increase in temperature.

B. Interactions in the system produce sound.

C. Mechanical energy is not conserved.

D. all of the above

2. 12. The mechanical energy of a system of objects is

A. the sum of kinetic energy and gravitational potential energy.

B. the sum of kinetic energy and elastic potential energy.

C. the sum of kinetic energy and all relevant forms of potential energy.

D. the sum of all forms of energy.

3. 13. Mechanical energy is not conserved when

A. gravitational potential energy is converted to kinetic energy.

B. kinetic energy is converted to gravitational potential energy.

C. kinetic energy is converted to elastic potential energy.

D. friction cannot be ignored.

4. 14. In which of the following situations is mechanical energy ALMOST conserved?

A. A football flies through the air.

B. A feather falls from the sky.

C. A figure skater gliding on the ice.

D. A hockey player digs his skates into the ice.

5. 11. Which of the following is true of the conservation of energy?

A. Kinetic energy is always conserved.

B. Potential energy is always conserved.

C. Mechanical energy is always conserved.

D. Total energy is always conserved.