Question

A balance and torque experiment is conducted with an UN-balanced ruler.

Length of the ruler: 1 m

Mass of the ruler: 207 g

The pivot is at the 38-cm mark.

A 59-g mass is located at the 76-cm mark of the ruler.

We want to balance the ruler by placing another mass at the 15-cm mark.

What should be magnitude of this additional mass?

Answer 1

Weight of ruler acts along the center of ruler

M = mass of ruler = 207 gm

59 gm

mass of object to be placed at 15cm mark

The ruler is pivoted at point O

For the ruler to remain balanced, net torque must be zero

Torque about O = τ =

Additional mass = 205.48 gm