Question

Kinetic energy of the bob of a simple pendulum is maximum:
A) At the mean position
B) At the extreme left position
C) At the extreme right position
D) None of these

Answer 1

Hint: As much as the faster an object moves, the more kinetic energy it will possess and it decreases as the bob moves further away from the equilibrium position.

Complete answer:
Let’s first understand about kinetic energy
Kinetic Energy is the energy which possessed by the body by virtue of its motion which means energy gained by the object by its motion,
$KE=\dfrac{1}{2}mv^2$
Kinetic energy is directly proportional to mass and velocity so by this we can conclude that as the velocity increases or mass of object increases the kinetic energy also increases.
So here mass is constant throughout the swinging but the velocity varies.
As well as at the extreme position both K.E and P.E is zero and by this work done is also zero here.
As the kinetic energy of the pendulum bob increases as the bob approaches the equilibrium position. And the kinetic energy decreases as the bob moves further away from the equilibrium position.
So the velocity of bob is zero at extreme position that is at extreme right or extreme left
So Kinetic energy is maximum at mean position because velocity is maximum at mean position

Hence option (A) is correct.

Note: Tension in the string is along the radius of circular path gained by the body while displacement of the bob is along the circumference of the path Hence, F and s are at $90^\circ$ and so, W=0.