Chapter 7, Problem 30A

To determine

To explain: The reason for acting a force on Moon according to Newton.

Explanation of Solution

Introduction:

Gravitational force:

Every object in the universe having some mass pull other object. The force is called gravitational pull or gravitational force.

The size of pull depends upon the masses of the objects and the distance between them.

The gravitational force is given by,

  $F=\frac{G{m}_1{m}_2}{r^2}$

Where, $G$ is the gravitational constant, $m_1$ and $m_2$ are mass of objects and $r$ is the distance between the objects.

According to Newton’s law of gravitation, there must be a gravitational force between the earth and the moon. It means the moon and the earth should have collided or moon should have fall down on earth. But nothing happened.

It means there is some other force which keeps the moon from falling dawn.

Since the moon is revolving and if there is no gravitational force present, the moon can go tangentially in a straight line.

So, the gravitational force holds the moon around earth.

Hence, there are forces acting on the moon.