In simple harmonic motion, the speed is greatest at that point in the cycle when
a. the magnitude of the acceleration is a minimum.
b. the kinetic energy is a minimum.
c. the magnitude of the acceleration is a maximum.
d. the displacement is a maximum.
e. the potential energy is a maximum.
The restoring force in a simple harmonic oscillator acts as a restoring force, acting opposite in direction of and proportional in magnitude to the displacement. This has the result that when the oscillator reaches the equilibrium point, it has gained its maximum kinetic energy (and therefore velocity) while the magnitude of the restoring force, and therefore the acceleration, is 0.
