Simple harmonic motion trouble

[Lalasushi]

hey guys im having trouble figuring out if something is undergoing simple harmonic motion. i know that for an object to be executing simple harmonic motion, its position and velocity must follow a sin curve...but im still having trouble. ok for example, a question on a worksheet said "a basketball player dribbles a ball with a steady period of T seconds. is the motion simple harmonic?" the answer was no. but i dont understand. how do u tell if its postiion and velocity follows a sin curve? can anyone explain to me?

 

[MalleusScientiarum]

When the particle is changing direction, does its velocity go to zero? If so, you're looking at something that could be simple harmonic.

 

[siddharth]

If the force on an object is directly propotional to the displacement of an object, but in a direction which is opposite to the displacement, then the object will undergo Simple Harmonic motion.
ie,
F=-kx
Now, can you see why the basketball bouncing is not Simple Harmonic motion?