Question

Natural length of the spring is 40 cm and its spring constant is 4000 N m–1. A mass of 20 kg is hung from it. The extension produced in the spring is (Given g = 9.8 m s–2)

• A. 4.9 cm
• B. 0.49 cm
• C. 9.4 cm
• D. 0.94 cm

Answer 1

Answer: (A)

4.9 cm

Answer 2

In equilibrium, kx = mg

$\therefore x = \frac{mg}{k} = \frac{20 \times 9.8}{4000}$

$= 0.049m = 4.9cm$