"It takes 100J of work to stretch a spring 0.5m from its equilibrium position. How much work is needed to stretch it an additional 0.75m." Attempt: w = ⌠abF(x)dx work = F x D 100J = F x 0.5m F = 200J 0.75 + 0.5 = 1.25 w = ⌠0.51.25 200dx w = 150 J The correct answer: w = 525 J what did I do wrong? Thanks! Nevermind, I found the exact problem online, so sorry!