Description: Work is a measurement of force across a distance. 
Key Terms: Work, force, distance, gravity, Newton, jewel

We see that the definition of work involves both a force and a distance. A
weightlifter who holds a barbell weighing 1000 newtons overhead does no work on
the barbell. He may get really tired holding the barbell, but, if it is not moved by the force he exerts, he does no work on the barbell. Work may be done on the muscles by stretching and contracting, which is force times distance on a biological scale, but this work is not done on the barbell. Lifting the barbell, however, is a different story. When the weightlifter raises the barbell from the floor, he does work on it.