# Newton’s Laws of Motion: Definition with Example

1.    Newton’s Laws of Motion: The father of physics newton give his law of motions in his book ‘Principa’ in 1687.

First law of Motion:  Every body continues to be in its state of rest or of uniform motion in a straight line unless compelled by some external force to act otherwise. This law also called Law of inertia and it gives definition of force.

For example, a spaceship out in interstellar space, far from all other objects and with all its rockets turned off, has no net external force acting on it. Its acceleration, according to the first law, must be zero. If it is in motion, it must continue to move with a uniform velocity.

Second law of Motion: The rate of change of momentum of a body is directly proportional to the applied force and takes place in the direction in which the force acts. This law defines strength of force.

If F is Force applied , m is mass of body  and a is acceleration produced :--

F= ma

Third law of Motion:  To every action, there is always an equal and opposite reaction.

Some examples of third law are

·       Motion of rocket

·       Recoil of gun

·       Earth pull the stone due to gravity

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