1. The problem statement, all variables and given/known data A mass (m = 1.35 kg), originally at rest, sits on a frictionless surface. It is attached to one end of an unstretched spring (k = 747 N/m), the other end of which is fixed to a wall (see figure below). The mass is then pushed with a constant force to stretch the spring. As a result, the system (which consists of the wall, spring and mass) comes to a momentary stop after the mass moves 15.0 cm. Find the following. (e) speed of the mass 4.50 cm into the motion 2. Relevant equations 3. The attempt at a solution I tried 1/2mv^2 = 1/2K (x1^2-x2^2) v= sqrt(K ( (0.15^2-0.045^2))/m not sure how to solve this .. been at it for a while now.