Question

A simple pendulum of lenght 1m has a bob of mass 100g. It is displaced through an angle of 60 from the verticle and then released . Find out ke of bob when it passes through mean position.

Answer 1

The question is based on the energy conservation. The potential energy of the bob at a height will get converted into the kinetic energy of the bob at the mean position.

Initial energy of the bob = Potential energy = Mass × height × gravity

Potential energy = 0.1 × (1 - 1×Cos 60°) × 9.8

Potential energy = 0.1 × 0.5 × 9.8 = 0.49 J

Now, formula for kinetic energy = $\(\frac{1}{2} \times m \times v^2\)$

Applying energy conservation:

Potential energy = kinetic energy

$\(\frac{1}{2} \times 0.1 \times v^2\)$ = 0.49 J

Hence, the Kinetic energy at the mean position is 0.49 J.