question_answer

Length of a simple pendulum is l and its maximum angular displacement is q, then its maximum K.E. is                    [RPMT 1995; BHU 2003]

A)            \[mgl\sin \theta \]             

B)            \[mgl(1+\sin \theta )\]

C)            \[mgl(1+\cos \theta )\]   

D)            \[mgl(1-\cos \theta )\]

Correct Answer: D

Solution :

                   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            Þ \[{{K}_{\max }}=mgh=mgl(1-\cos \theta )\]