Question

The amount of extension in an elastic string varies directly as the weight hung on it. If a weight of 150 gm produces an extension of 2.9 cm, then what weight would produce an extension of 17.4 cm?

Answer 1

Let us consider the weight produce be ‘x’ gm.

Extension (cm)	2.9	17.4
Weight (gm)	150	x

2.9/150 = 17.4/x

By cross-multiplying

2.9x = 150(17.4)

2.9x = 2610

x = 2610/2.9

= 900

∴ 900 gm of weight is produced for an extension of 17.4 cm.