Ablock of mass m 0.750 kg is fastened to an unstrained hor- izontal spring whose spring constant is k 82.0 n/m. the block is given a displacement of 0.120 m, where the sign indicates that the dis- placement is along the x axis, and then released from rest. (a) what is the force (magnitude and direction) that the spring exerts on the block just before the block is released