Dear fellows I have three questions related to the topic “Lifting an object against gravity”. If we lift an object of mass 5kg we need to apply a little more force than its weight to lift it and suppose we apply 50 N force (gravity is exerting 49 N forces on it) for just a second that produces 0.2 m/s/s acceleration in the body and then we reduce the force to 49N after a second, now according to Newton’s first law the body will keep moving upward with constant velocity (0.2 m/s). Am I right??????????? When we apply 50N force for a second this force does 0.1J of work on the body. Now during the lift we can’t say that the net work done is 0. Am I right?????????? When we make the body to be in rest position, we need to reduce the upward force for just 1N and as a result the net force will be downward and that will be 1N. Now this net force will do 0.1J of work in opposite direction or -0.1J and this will cancel out the 0.1J of work that was in upward direction. This is why we say that when we lift a book from table to shelf the net work done is 0. Am I right???????