A spring of force constant 50 N/m is stretched by 4 m. What will be the potential energy stored in the spring?
Correct: B
Potential energy (U) stored in a spring is given by U = 1/2 kx^2, where k is the force constant and x is the displacement. Given, k = 50 N/m, x = 4 m. Substituting these values gives U = 1/2 × 50 × (4)^2 = 400 J.