- #1

CoreanJesus

## Homework Statement

A projectile of mass M1 is fired horizontally from a spring gun that is initially at rest on a frictionless surface. The combined mass of the gun and projectile is M2. If the kinetic energy of the projectile after firing is K, the gun will recoil with a kinetic energy equal to...

## Homework Equations

this is part of the problem.

I know you need the kinetic energy formula but I don't get the other formula.

## The Attempt at a Solution

N/A Answer is (M1/(M2-M1))K