Question

11. A highly compressed spring releases 2 J of elastic potential energy when allowed to expand 1 mm, a small fraction of its over- all compression. How much force is the spring exerting on its end?

Answer 1

x = expansion of the spring = 1 mm = 0.001 m

U = spring potential energy released = 2 J

k = spring constant

Using the equation

U = (0.5) k x²

2 = (0.5) k (10^-3)²

k = 4 x 10⁶ N/m

F = spring force

Spring force is given as

F = k x

F = (4 x 10⁶) (10^-3)

F = 4000 N