1. The problem statement, all variables and given/known data An object has a mass of 10 lbm. b. Find the change in kinetic energy ft·lbf when its velocity decreases from 50 mph to 15 mph. 2. Relevant equations KE=1/2mv^2 Ke=(ft*lbf) 1MPH=1.4667 ft/s 3. The attempt at a solution When calculating this, does it need to be in slugs, lbm, or lbf? I'm not too familiar with english units.