Question: A block of mass m is pushed up against a spring, compressing it a distance x, and the block is then released. The spring projects the block along a frictionless horizontal surface, giving the block a speed v. The same spring projects a second block of mass 3m, giving it a speed of 3v.
Part A: What distance was the spring compressed in the second case?
I need help to find what distance was the spring compressed in the second case.