The launching mechanism of a toy gun consists of a spring of unknown spring constant?

Question

If its spring is compressed a distance of 0.180 m and the gun fired vertically as shown, the gun can launch a 21.0 g projectile to a maximum height of 18.0 m above the starting point of the projectile.

(a) Neglecting all resistive forces, determine the spring constant.
______N/m

(b) Neglecting all resistive forces, determine the speed of the projectile as it moves through the equilibrium position of the spring (where x = 0)_______m/s

need help one this one guys. Thanks

Answer 1

energy stored = 1/2kx^2 =1/2k*(0.18m)^2

potential energy change = mgh = mg*(18m)