Speed of a spring

Question

A spring is pressed against a wall so that it is compressed by 0.25 m (i.e. it is 0.25 m shorter than the equilibrium length), The spring is then released. The spring constant is k = 35 N m^-1 and the spring weighs 50 g. What is the speed at which the spring leaves the wall?

Answer 1

The potential energy of the compressed spring must equal the kinetic energy of the spring.

m = mass of spring = 0.050 kg

k = spring constant = 35 N/m

x = compression distance = 0.25 m

v = spring speed = ?

mv² / 2 = kx² / 2

v = √(kx² / m)

Now plug in the numbers and get v in m/s.