1. The problem statement, all variables and given/known data The Internal energy of fuel in a combustion chamber increases by 75J due to 130J of heating. How much work can be done by the piston? How far does the piston move while pushing with 5000N of force? 2. Relevant equations 3. The attempt at a solution Since they gave us the info to find efficiency i divided 75J by 130J and got 57.7% eff. I plugged that into (e= w/QH) and got work = 75.01J and i plugged it into w=F *(delta x) and got .015m. I'm not sure if this is right, but the units seem to be correct.