Question

Simple pendulum of length l has a maximum angular displacement $\theta$. The maximum kinetic energy of the bob is?

• A. mgl$(1-\cos \theta )$
• B. $0.5$mgl
• C. mgl
• D. $2$mgl

Answer 1

The correct option is A mgl$(1-\cos \theta )$

In the equilibrium position energy is in the form of kinetic energy.
Height of bob at maximum angular displacemeny is
$h=l-l\cos \theta$
$=l(l-\cos \theta )$
Also PE$=$KE
mgh$=$mgl$(1-\cos \theta )$.