What provides the restoring force of simple harmonic oscillations in the following cases:

cbse
oscillations

#1

What provides the restoring force of simple harmonic oscillations in the following cases:
(i) simple pendulum, (ii) spring, (iii) column of mercury in U-tube ?


#2

The sources of restoring force is as follows:
(i) Simple pendulum : gravity.
(ii) Spring: elasticity
(iii) Column of mercury in U tube : weight.