1. The dilemma Work (change in energy) is defined as the exertion of a force over a distance parallel to the force. So if force is exerted, but nothing is moved (presumably with two immovable objects), then no energy is changed. But think about the dilemma with a person lifting 100 pounds above his head. He exerts a force of 100 pounds to counter the weight, and say he keeps it above his head for 1 hour. According to the work equation, the person has changed 0 energy in doing this act. But he has continually exerted a force of 100 pounds for 1 hour, and now he is very tired. But according to work, he has spent 0 energy. What am I missing?