Question

A uniform metre scale balances horizontally on a knife edge placed at 55cm mark, when a mass of 25g is supported from one end. Draw the diagram of the arrangement. Calculate mass of the scale.

Answer 1

As the metre scale is balanced at 55cm mark i.e. large arm is balanced by arm BC and 25g is suspended at one end i.e. at 100cm mark 

∴ Anticlockwise moment = clockwise moment W × (55 – 50) = 25 × (100 – 55)W = 25 × 45/5 = 225g