A string of length 5cm is extended by 0.04m when a load of 0.8kg is suspended at the end. How far will it extend if a force of 16N is applied? [g = 10ms\(^{-2}\)]

A.

0.04m

B.

0.12m

C.

0.01m

D.

0.08m

Correct answer is D

From Hoke's Law, F = ke, K = Constant of Force

For he first case, Force = mg,

= 0.8 × 10 = 8N

∴ 8 = k × 0.04

k = \(\frac{8}{0.04}\)

= \(\frac{200N}{m}\)

Since K is constant

For the second case, F = ke

F = 200 × e

∴ e = \(\frac{F}{200}\)

= \(\frac{16}{200}\)

= 0.08m