Without energy we can't do work cuz we can't apply ne force on an object. Gravity, itself a force, when, say, pulls a ball down to the gorund it actually does work. Now for that force, where does it get the energy from or what type of energy does it have?

If u have a book opened n u hold a page up frm it n then leave it so that it slides down to it's original poisition, has work been done by the gravity?

The work gravity does is increasing the kinetic energy of the falling object, dissipating that kinetic energy into heating and moving air (air friction).

I am not certain what your second question is, it is far from standard English. When one separates two objects, one does work against gravity, when the objects come closer, gravity does work.



To answer your first question, gravity gets its energy from the potential energy of the object it is acting upon. When an object is lifted or separated from the ground, it gains potential energy due to its elevated position. This potential energy is then converted into kinetic energy as the object falls or moves towards the ground under the influence of gravity. So, in short, gravity obtains its energy from the potential energy of the object.

For your second question, when you hold a page of an opened book up and then release it, allowing it to slide down to its original position, gravity does do some work. As the page falls, gravity acts as a force pulling it downwards. This force exerts energy on the page, which is transferred into kinetic energy as the page gains speed while sliding down. So, in this case, gravity is doing work on the page by transferring its potential energy into kinetic energy.