Compute the work required to stretch a spring from equilibrium to 7 cm past equilibrium, assuming that the spring constant is k=160kg/s^2 W =______ J

Answer 1

Mechanical work is force * displacement; incremental work dW = F cos θ dx = kx dx for a spring. The negative sign on the force gets cancelled by θ being 180 degrees between force and displacement.

So W = ∫ 160 x dx = 160 [x² /2] evaluated from x = 0 to x = 0.07 m. Then W = 80 (0.07)² = 0.39 Joules.