1. The problem statement, all variables and given/known data One end of a horizontal spring with force constant (76.0 N/m) is attached to a vertical post. A 4.00-kg can of beans is attached to the other end. The spring is initially neither stretched nor compressed. A constant horizontal force of 57.0 N is then applied to the can, in the direction away from the post. Part A What is the speed of the can when the spring is stretched 0.400 m? Part B At the instant the spring is stretched 0.400 m, what is the magnitude of the acceleration of the block? 2. Relevant equations Us = 1/2kx^2 Ke= 1/2mv^2 3. The attempt at a solution I considered setting 1/2kx^2 =1/2mv^2 and solving for "v". I got the answer 1.74m/s which is incorrect. As for part B I considered using the equation F =ma. 57N = 4kg(a) a = 57/4 = 14.25 m/s^2. However that was incorrect as well. Please assist! I have no idea where to go from here.