A block of mass 1.3 kg is attached to one end of a spring (with spring constant 8 Nlm) whose other end is fixed to a wall. The block sits on a frictionless table. The mass is pulled 0.4 m from it's equilibrium position and released. What is the force acting on the block when it is travelling at it's maximum velocity? $51? N/m What is the magnitude of the force acting when the block has a speed of half of it's maximum value? $51? N