I'm figuring that this has been asked before, but I couldn't locate a previous thread. Here's my problem: A 1.0 kg ball is lifted at a constant speed to a height of 1.0 meter above the ground. The work done to the ball against gravity is about 10 joules. The same 1.0 kg ball is lifted with a force of 15 newtons to a height of 1.0 meter above the ground. The work done to the ball in this case is 15 joules. What is getting me confused is that the work done to lift the ball 1.0 meter should be the same no matter what. And the work energy theorem says that a 1.0 kg object 1.0 meter above the ground should have a GPE of 10 joules. So my problem is with lifting objects with a force greater than their weight. What am I getting mixed up here?