Understanding Mechanical Energy

Which of the following best defines mechanical energy?

• Energy due to the motion or position of an object

• Energy released from chemical reactions

• Energy stored in atomic nuclei

• Energy from the sun

What happens to the kinetic energy of a freely falling object as it falls?

• It increases.

• It decreases.

• It stays constant.

• It becomes zero.

A pendulum is swinging back and forth. At its highest point, the pendulum has:

• Maximum kinetic energy and no potential energy

• No kinetic energy and maximum potential energy

• Equal kinetic and potential energy

• No mechanical energy

Which of the following correctly expresses the relationship between kinetic energy (KE), potential energy (PE), and total mechanical energy (TME)?

• 𝑇𝑀𝐸=𝐾𝐸-𝑃𝐸

• 𝑇𝑀𝐸=𝐾𝐸/𝑃𝐸

• 𝑇𝑀𝐸=𝐾𝐸 +𝑃𝐸

• 𝑇𝑀𝐸=𝐾𝐸 x𝑃𝐸

If a 10-kg rock falls from a height of 20 meters, how much kinetic energy will it have just before hitting the ground? (Ignore air resistance and use ag)

• 19.6 J

• 98 J

• 980 J

• 1,960 J