Question

A closed system consists of a pendulum that is swinging back and forth. If the kinetic energy of the pendulum INCREASES, what else must happen to the energy of the system?

A. Its gravitational potential energy must decrease.
B. Its total mechanical energy must decrease.
C. Its gravitational potential energy must increase.
D. Its total mechanical energy must increase..

Answer 1

Answer: it’s A

Explanation: I just took the test

Answer 2

Both C and D are true.

Energy goes from total kinetic to total gravitational

If Kinetic energy increases then the gravitational energy at its maximum displacement will also increase.

E (total) = PE + KE at any point of the motion