I would like to know..What is harmonic motion??
and What is SIMPLE Harmonic Motion??..basically the difference between the two...

Examples for the same would be very much appreciated... Thanks a lot..

and also where does oscillation fit into??

Oscillation is “to and fro” motion, that is, the direction of motion is reversed periodically.

Harmonic motion is that motion in which the particle oscillates about an equilibrium position due to a restoring force/torque. It is simple harmonic if this restoring force/torque is directly proportional to displacement of particle from equilibrium position. Example for harmonic motion is simple pendulum and example for simple harmonic motion is mass-spring system.

Approved