# Work in the opposite direction [duplicate]

If I lift an object with a specific force, the force does work on the object and energy gets stored in the object in the form of potential energy (m * g * h (h = height)). But there is also a force downwards - the gravitational force which also does work, doesn't the energy equal the gravitational work minus the work I do to lift it up, but that is very close to 0 which seems weird compared to excercises i've done on work.

Because when a car drives, it has a force on it which pushes it forward therefore the force does work on the car, but there is also a force of friction on the car, which also does work which brings to my first question: do you subtract the friction work with the work that drives it forward to ultimately get the energy or the kinetic energy in this case of the car?

second question: if the work is net zero when it's in certain height how does this work of net zero become kinetic energy if there isn't any energy when i drop it from that certain height?

I hope you somewhat understand my problem, if there's any grammatical mistakes or such just tell me and I'll fix

• Possible duplicate of Net work done on the body when we lift it and put it on the table is zero? – sammy gerbil Jun 7 '17 at 16:15
• What exactly is the question? The text needs some line-breaking and periods. – Steeven Jun 7 '17 at 16:19
• @sammygerbil, the answer to the question is kind of my problem , if the work is net zero when it's in certain height how does this work of net zero become kinetic energy if there isn't any energy when i drop it from that certain height? – Iram Haque Jun 7 '17 at 16:19
• Fixed the questions @Steeven – Iram Haque Jun 7 '17 at 16:22
• As the answer explains : you did +ve work, gravity did -ve work. That -ve work is stored as PE in the gravitational field. It came from the chemical energy in your body. When the object is dropped, its KE comes from the stored gravitational PE, not from the net work done on the object. – sammy gerbil Jun 7 '17 at 16:38