a question about springs?

Question

A gun that shoots corks of mass 0.0045 kg uses a spring of spring constant 9.6 N/m. The b = 0.22 m long spring is compressed to a = 0.13 m. Its 0.22-m long barrel exerts a constant 0.26 N force of friction on the cork when the gun is fired. What is the cork’s speed in m/s at the muzzle of the gun?

Answer 1

A typical conservation-of-energy problem.

The initial energy of the system is the potential energy of the spring, 1/2 k x^2.

The final energy of the system is the kinetic energy of the cork, 1/2 m v^2, less the work done by the barrel, Fd.

The equation you must solve is 1/2 k x^2 = 1/2 m v^2 + Fd
You know everything except v.