solve fully, use diagrams if needed

12.A toy gun fires a 9.41-g projectile disc by using a compressed spring (k = 17,200 N/m) and a 13.1 cm long barrel. As the disc travels through the barrel, it experiences a constant frictional force of 0.13 N. If the spring is compressed 14 mm, what is the speed of the disc as it leaves the gun? [4 marks]