A mass and spring are arranged on a horizontal, frictionless table. The spring constant is k = 450 N/m, and the mass is 5.4 kg. The block is pushed against the spring so that the spring is compressed an amount 0.35 m, and then it is released. Find the velocity of the mass when it leaves the spring.

Answer 1

potential energy stored in spring = kinetic energy of block

(1/2) k x^2 = (1/2) m v^2

450 (.35)^2 = 5.4 v^2