Question

A spring 40 mm long is stretched by the application of a force. If 10 N force required to stretch the spring through 1 mm, then work done in stretching the spring through 40 mm is

• A. 84 J
• B. 68 J
• C. 23 J
• D. 8 J

Answer 1

Answer: (D)

8 J

Answer 2

Here $k = \frac { F } { x } = \frac { 10 } { 1 \times 10 ^ { - 3 } } = 10 ^ { 4 } \mathrm {~N} / \mathrm { m }$

W