Two Scenarios: 1. I have to push a cart. I apply a constant force of 10 newtons in the horizontal direction. The cart moves for 10 meters. I have done 100 Nm or Joules of work. 2. I push the cart but I don't follow it and apply a constant force. It was just one moment of force, let's say 100 N. The cart moves forward, then friction eventually stops it after 10 meters in the direction that I pushed. Have I done 1000 Nm or Joules of work? I don't think I have, but can someone explain to me the difference?