1. The problem statement, all variables and given/known data A cannon that weighs 500 lbs shoots a cannonball horizontally that weighs 20 lbs at 400 m/s while mounted in place so that it does not move. If the same cannon and cannonball are shot in the same way with the cannon mounted on wheels allowing it to recoil, what is the new muzzle velocity? 2. Relevant equations p=mv p1=p2 KE= (1/2)mv2 mcvci + mpvpi = mcvcf + mpvpf Where: mc= Mass of the cannon, mp= Mass of the projectile, vci= Initial velocity of the cannon, vpi= Initial velocity of the projectile, vcf= Final velocity of the cannon, vpf= Final velocity of the projectile. 3. The attempt at a solution I am really quite lost here. I have tried a bunch of stuff, but can't seem to get the answer. I tried finding the velocity of the cannon's recoil and using it to figure out the new muzzle velocity, but I got an answer that was too low. I have also tried using KE1=KE2, but I don't think that that formula is applicable because I don't think that energy is conserved. Thanks for any help!