Hookes Law In Homework Help Posted January 19, 2014 Hi, For the following question: A 1.37-kg fish is hung from a vertical spring scale with a force constant of 5.20x10² N/m. The spring obeys Hooke’s Law. (a) By how much does the spring stretch if it stretches slowly to a new equilibrium position? ( If the fish is attached to the un-stretched spring scale and allowed to fall, what is the net force on the fish when it has fallen 1.59 cm? © Determine the acceleration of the fish after it has fallen 2.05 cm. http://www.dpcdsb.org/NR/rdonlyres/70ACCCCE-D6A6-44CA-982F-8E319A8ADE82/89746/momentumenergyquestions.pdf (the solution is posted here). I was wondering why you have to use forces to solve(kx) rather than the formula for elastic potential energy(kx/2). When I tried using energy, it did not give me the same answer. Why would energies not work? Thank you in advance for taking the time to answer my question.