Problem # 1

Initially (t=0), the 15 kg block is at rest (v=0) at the position x=0.8m with the spring being already extended by 0.2 m from its unstretched length. The spring constant is k=50 N/m, the coefficient of friction between the block and the inclined surface is 0.2. Under influence of gravity the block will start to slide down the incline.
From its initial position (x=0.8m) the block slides by 1m to x=1.8m. For this movement determine :
  1. The work done by the weight of the block
  2. The work done by the friction force (be careful with the normal force)
  3. The work done by the spring
  4. and finally the velocity of the block when it has reached x=1.8m.