Concepts of Physics

IIT JEE Physics (1978-2018: 41 Years) Topic-wise Complete Solutions

The Physics of the Beam Balance

Objective

To study the physics of balance

Introduction

For a body to be in equilibrium, the net force and net torque should be zero. The setup consists of a scale hinged at its middle point. The scale has holes at regular interval to hang weights at different distances from the hinge point.

Apparatus

slotted weights, thread, setup with scale

Procedure

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  • Check that scale is almost balanced. If not, fix a suitable weight to balance it.
  • Attach a fixed weight at one end of the scale.
  • Attach another weight on other side of hinge point so that scale is balanced.
  • Repeat above step for different weights.
  • Verify that net force on the scale and net torque about the hinge point is zero in balanced condition.

Note

According to lever principle, a smaller force applied at a greater distance from the axis of rotation can lift a larger weight.