Question

A stack of books is sitting on a table. Which force is pulling downward on it?

Answer 1

There's a pair of gravitational forces between the stack and the Earth. 

One gravitational force is pulling the stack toward the center of the Earth.

The other gravitational force is pulling the Earth toward the center of the stack. 

The forces are equal.

Answer 2

Answer:

Gravitational force

Explanation:

Gravitational force is pulling stack of books towards the center of earth. it is the force which acts between two objects with masses. Gravitational force is one of the four universal forces. Gravitational force is directly proportional to the products of the masses of two bodies and divided by the square of distance between these two bodies.