Today my university home work

Industrial usage of torsion pendulum
The working of " Torsion pendulum clocks " ( shortly torsion clocks or pendulum clocks), is based on torsional oscillation.
2.The freely decaying oscillation of Torsion pendulum in medium(like polymers),helps to determine their characteristic properties.
3.New researches, promising the determination of frictional forces between solid surfaces and flowing liquid environments using forced torsion pendulums.

Damping
Damping is an influence within or upon an oscillatory system that has the effect of reducing, restricting or preventing its oscillations. In physical systems, damping is produced by processes that dissipate the energy stored in the oscillation.

Eddy currents
Eddy currents (also called Foucault currents) are loops of electrical current induced within conductors by a changing magnetic field in the conductor due to Faraday's law of induction. Eddy currents flow in closed loops within conductors, in planes perpendicular to the magnetic field

Definition
The magnitude of the current in a given loop is proportional to the strength of the magnetic field, the area of the loop, and the rate of change of flux, and inversely proportional to the resistivity of the material.

Example
Relative motion between a magniet and a near by conductor.