WE CALCULATE POWER AND RATE OF DOING WORK IS CALLED POWER
Answer:
ya I just looked it up on Google
The answer is Gravity
There's always a gravity between any 2 objects in this universe. between you and your computer, between you and the floor, between your chair and your table, etc.
We just dont feel it because we live in earth which negates all of those gravities with its own.
C. A child can pass through the stages in any order.
They would all strike the ground at the same time. If air resistance is neglected for example in an airless tube, then gravity is the only force acting on them and it has the same effect on them dropping so the drop at the same speed.