A spring with k = 50 N/m is compressed by x = 0.1 m. What is the potential energy stored?

• A. 0.5 J
• B. 0.125 J
• C. 2.5 J
• D. 0.25 J

Answer: (D)

Energy stored in a spring comes from its elastic potential energy, given by U = 1/2 k x^2, where k is the spring constant and x is the displacement from equilibrium. This shows the energy grows with both stiffness and how far the spring is compressed or stretched.

Plugging in k = 50 N/m and x = 0.1 m:

U = 1/2 × 50 × (0.1)^2 = 25 × 0.01 = 0.25 joules.

So the potential energy stored is 0.25 J.