1. The problem statement, all variables and given/known data A person is standing on a sheet of ice so slippery that friction may be ignored. This individual fires a gun parallel to the ground. When a standard cartridge is used , a 17-g bullet is shot forward with a speed of 280 m/s, and the person recoils with a speed of vc. When a blank cartridge is used , a mass of 0.13g is shot forward with a speed of 53 m/s , and the recoil speed is vb. Find the ratio vb/vc. mass of bullet = 0.017 kg mass of blank = 1.3e-4 kg 2. Relevant equations KE = 1/2mv^2 ? 3. The attempt at a solution I tried using that equation and solved for KE of the bullet (666.4 J) and the KE of the blank (0.1825 J) but I don't know if that's useful or not. I'm not given the mass of the person, and I don't just want to assume 60 kg. I know I'm supposed to attempt to do the problem before asking for help, but I don't even know where to start.