I'm an adult doing the self-education thing, having dropped out of high-school (big mistake, incidentally). I have a couple basic physics questions that I can't seem to find the answers to: 1) If F=ma, why do all objects the same distance from the earth's surface accelerate at 9.8 m/s^2? Shouldn't objects of greater mass accelerate more slowly, according to Newton's second law (assuming Earth's gravity is constant)? 2) W=Fd (where W="work"), but, when I lift an object 4 meters at a constant speed I am said to have done twice as much work as if I had lifted it 2 meters at a constant speed. This seems strange to me, since, in both cases, the initial acceleration of the object (as it goes from being at rest to moving at a constant speed) is the only non-zero force involved. Since the distance after that is travelled at a constant speed (F=m(0)=0), shouldn't it add nothing to the total force required to lift the object? I know, intuitively, that there is something wrong with my reasoning in both of these questions, but I can't quite figure what it is. Help would be appreciated.