posted by velet on .
A 0.44-kg block is hung from and stretches a spring that is attached to the ceiling. A second block is attached to the first one, and the amount that the spring stretches from its unstretched length triples. What is the mass of the second block?
because length is proportional to force, the second set of masses must be three times the first, but the second set of masses is .44kg+secondmass, so second mass is twice the first.