Damping

Damping forces oppose the motion of the oscillating body, they slow or stop simple harmonic motion from occurring. Damping forces act in the opposite direction to the velocity.

Galileo made an important observation while watching lamps swing in Pisa cathedral. He noticed that the swinging gradually died away but the time taken for each swing stayed roughly the same. The swing of the lamp was being damped by air resistance.

Light damping slowly reduces the amplitude of the oscillations, but keeps the time period almost constant.

Heavy damping allows the body to oscillate but brings it quickly to rest.

Critical damping brings the body back to the equilibrium point very quickly with out oscillation.

Over damping also prevent oscillation but makes the body take a longer time to reach equilibrium.