1. The problem statement, all variables and given/known data http://img198.imageshack.us/img198/9417/springenergy.jpg [Broken] A) A body moves on a horizontal surface at a constant velocity of V = 2 m/s as described in pic A. In its way it hits point B at the spring in its horizontal position, whose in relaxed position. The mass of the body is m = 1 kg and the spring's constant is k = 80 N/m Calculate how much will the spring shorten as a result from the body hitting it presuming the surface is frictionless. B) The body is released from the spring at point B, at an initial velocity of V = 2 m/s as described in pic B. At what horizontal distance from point B will the body move to after being released from the spring, if the kinetic friction coeffecient between the body and the plain is μ = 0.25. The mass of the body is idential to caluse A. You must do the calculations in 2 ways: 1) By considering work and energy 2) By Newton's second law (sigma F = ma) 2. Relevant equations 3. The attempt at a solution http://img705.imageshack.us/img705/8687/mghinaction1.jpg [Broken] http://img8.imageshack.us/img8/3046/mghinaction2.jpg [Broken] ( I don't have the solution manual answer to that, but I think this is correct ) I'm getting a bit stuck at clause B. I wanna draw a free body diagram, but I'm not sure what I should use for force. Should I use F = 80 x 0.224 Or should I discover my force doing sum of all forces on x = ma?