Question

A uniform metre scale can be balanced at the 70.0 cm mark when a mark when a mass 0.05 kg is hung from the 94.0 cm mark

1. draw a diagram of the arrangement
2. Find the mass of the metre scale

Answer 1

1) A diagram of the given arrangement is shown below.

2) As the given meter scale is a uniform scale. So its centre of gravity lies at 50 cm. Let the mass of the meter-scale be W₁ kg.

From the principle of moments

Anticlockwise moment = clockwise moment

 m₁x₁ = m₂x₂

m₁ × (70 − 50) = 0.05 × (94 − 70)

m₁ = `(0.05 xx 24)/20`

= 0.06 kg

= 60 g