Hello PF, I have a problem that I cannot solve. Assuming my car weighs 4000 pounds with passengers and cargo and is travelling at 100 feet per second, this requires 4000lb*100ft/s = 400,000 ft-lb/s or 727.3 hp of work. But I know the engine is only producing about 50 or 60 hp, and I'm maintaining speed! So... what gives? What am I missing? Thank you so much for your help!