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

• Correct answer
  A

  $m g l(1-\cos \theta)$
• B

  0.5 mgl
• C

  mgl
• D

  2 mgl

Solution

In the equilibrium position energy is in the form of kinetic energy. Height of bob at maximum angular displacement is $\begin{aligned} h & =l-l \cos \theta \\ & =l(1-\cos \theta) \\ \text { Also } \mathrm{PE} & =\mathrm{KE} \\ m g h & =m g l(1-\cos \theta)\end{aligned}$

Hence, the correct answer is option: 'A'.