Block A in the figure below has mass 1.30 kg , and
block B has mass 2.85 kg . The blocks are forced together,
compressing a spring S between them; then the system is
released from rest on a level, frictionless surface. The spring,
which has negligible mass, is not fastened to either block and
drops to the surface after it has expanded. Block B
acquires a speed of 1.20 m/s .
Part A
What is the final speed of...