A simple pendulum of length 100 cm performs S.H.M. Find the restoring force acting on its bob of mass 50 g when the displacement from the mean position is 3 cm.
As per the given question,
we can list out the given quantity
Length L = 100 cm = 1m,
mass m = 50 g = 50 x $10^{-3}$ kg
displacement x = 3 cm = 0.03m ,
g = 9.8 m/$s^2$
To find = Restoring force, F = ?
Solution –
Restoring force, F =mg sin θ = mgθ
(Since for small angle θ, sin θ = θ)
F = mg x $\frac{x}{L}$
F = 5 × $10^{-2}$ x 9.8 x 0.03
F = 1.47 × $10^{-2}$ N