1. The problem statement, all variables and given/known data A block of mass m = 0.1 kg is connected to a spring of unknown spring constant k. It is compressed to a distance x from its equilibrium position and released from rest. After approaching half the distance (x/2) from equilibrium position, it hits another block and comes to rest momentarily, while the other block moves with a velocity 3 m/s. The total initial energy of the spring is: 1.5 J 0.6 J 0.3 J 0.8 J 2. Relevant equations Spring potential energy is 1/2 kx2 In this question we have to do basically energy balance 3. The attempt at a solution Isn't this question wrong? We should be given other block mass and told that it is an elastic collision?