Question

Length of a simple pendulum is l and its maximum angular displacement is $\theta$ then its maximum K.E.is

• A. $mgl\sin \theta$
• B. $mgl(1+\sin \theta )$
• C. $\mathrm{mgl}(1+\cos \theta )$
• D. $mgl(1-\cos \theta )$

Answer 1

The correct option is A $mgl\sin \theta$

Kinetic energy will be maximum at mean position.
From law of conservation of energy,

maximum kinetic energy at mean position $=$ Potential energy at displaced position
$\Rightarrow$ $K_{max}=mgh=mg(1-\cos \theta )$