Question

A pendulum is 0.150 m long, and the bob has a mass of 1.00 kg. At the bottom of its swing, the bob’s speed is 1.60 m/s.

What is the tension in the string at the bottom of the swing?

Answer 1

First we have to draw the free body diagram of the system.

There are three forces acting on the mass

Here, Fc is the centrifugal force

Since the string is rigid, these forces must cancel each other

So, the tension on the string is given by

The gravitational force is given by

W = mg,

where g = 9.8 m/s^2

The centrifugal force is given by

Here, m = 1.00 kg

r = 0.150 m

v = 1.60 m/s

So,