Question

Akash takes a uniform meter scale and suspends a weight of 2 N at one end ‘X’ and a weight of 5 N on the other end ‘Y’. He then balances the ruler horizontally on a knife edge placed at 70 cm from X. Draw a diagram of the arrangement and calculate the weight of the ruler.

Answer 1

For the meter scale to be in equilibrium, applying the principle of moments,

[2 × 0.7] + [W × (0.7 − 0.5)] = [5 × 0.3]

1.4 + W × 0.2 = 1.5

0.2 W = 1.5 − 1.4

0.2 W = 0.1

W = `0.1/0.2`

W = 0.5 N