1. The problem statement, all variables and given/known data It takes 241 kJ of work to accelerate a car from 22.0 m/s to 28.8 m/s. What is the car's mass? W = 241000 J vo = 22.0 m/s vf = 28.8 m/s m = ? 2. Relevant equations KE = 1/2 mv2 W = KEf - KEo 3. The attempt at a solution W = KEf - KEo W = 1/2 mvf2 - 1/2 mvo2 I was trying to solve for m as everything else is known, but I think I got stuck somewhere in the algebra. W = 1/2 (mvf2 - mvo2) 2W = mvf2 - mvo2 2W / vf2 - vo2 = m - m That's as far as I got. I'm wondering if by switching the sides of the equation so that their signs would change if then m - m could become m + m, thus 2m. Then divide both sides by 2. Does that seem right? Thanks!