The mysteries of Horsepower and other things explained

I used to explain it to the young punks that worked with me in the shop like this...
If I send two of u outside to push a broken car into the first bay, and ten minutes later I wonder where the heck you are... So I walk outside and see you two numb nuts sweating and pushing on the trunk but forgot to release the parking brake and the car wouldn't budge... YOU HAVE DONE NO WORK.... Sweaty force times 0 feet over any time equals 0 work done