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Simple Harmonic Motion - Multiple Choice Questions

Q8. Which one of the following statements is not true for a body vibrating in simple harmonic motion when damping is present?

A The damping force is always in the opposite direction to the velocity.
B The damping force is always in the opposite direction to the acceleration.
C The presence of damping gradually reduces the maximum potential energy of the system.
D The presence of damping gradually reduces the maximum kinetic energy of the system.

A damping force is a form of friction - it opposes movement and will therefore be in the opposite direction to velocity - so A is true.

Acceleration and velocity are not always opposite (see the graphs below) , so B is NOT true.

A damping force will transfer kinetic energy into heat energy thus gradually reducing the total energy of the SHM system - therefore C and D are true.