My question isn't a homework question, it's a general conceptual question. We were going over a "work" problem in class and our professor told us that the work required to lift an object up to a certain height was equal to "mgh". However, is this only the case when we assume that acceleration is zero? Work is equal to force times displacement, and the net force = ma. Therefore, if we say that the force we apply on an object to lift it up is equal to "mg", that means our net force = mg - mg= 0, which can only happen when acceleration equals 0, which is how we obtain W= (mg)(h). Am I right?