Question

The maximum angular displacement of simple pendulum of length $l$ is $\theta .$ Its maximum kinetic energy will be

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

Answer 1

Answer: (D)

$h=l-l\cos \theta$
The energy of pendulum at point A will be completely potential energy at point B will be kinetic energy.

$\Rightarrow$ $\frac{1}{2}m{v}^2=mgh$
$\frac{1}{2}m{v}^2=mgl(1-\cos \theta )$