Question

Discribe damped occillation

Answer 1

A parametric oscillator is a driven harmonic oscillator in which the drive energy is provided by varying the parameters of the oscillator, such as the damping or restoring force. A familiar example of parametric oscillation is "pumping" on a playground swing.
hope this helps.

Answer 2

Damped oscillations

We know that in reality, a spring won't oscillate for ever. Frictional forces will diminish the amplitude of oscillation until eventually the system is at rest.

We will now add frictional forces to the mass and spring. Imagine that the mass was put in a liquid like molasses. Your lab instructor will not like it when they see their nice metal weight coated with a thick layer of ants in the morning. Be that as it may, when the mass is inside the molasses, it'll hardly oscillate at all.

On the other hand, a mass in air oscillates many times before it comes to rest. To incorporate friction, we can just say that there is a frictional force that's proportional to the velocity of the mass. This is a pretty good approximation for a body moving at a low velocity in air, or in a liquid. So we say the frictional force . The constant  depends on the kind of liquid the mass is in and the shape of the mass. The negative sign, just says that the force is in the opposite direction to the body's motion. Let's add this frictional force in to the equation