# Newton's Law of Motion : Scince GK

Newton’s Law of Motion

This law is useful for GK or General Knowledge in Competition Examination:

Newton, the Father of physics established the laws of motion in his book “Principia” in 1687.

Newton’s First Law of Motion: Everybody maintains its initials state of rest or motion with uniform speed on a Straight line unless an external force acts on it. Newton’s first law is also called law of Galileo or law of Inertia. First law gives the definition of Force.
What is Inertia?
Inertia: Inertia is the property of a body by virtue of which the body opposes change in its initial state of rest or motion with uniform speed on a straight line. Inertia is of two types: 1. Inertia of rest, 2. Inertia of motion.
Example of Inertia:
1. When a car or train starts suddenly, the passengers bends backward.
2. When a car stops suddenly, the passengers bends forward.
3. When a coat/blanket is beaten by a stick, the dust particles are removed.
Force: Force is that external cause which when acts on a body changes or tries to change the initial state of rest or motion with uniform velocity of the body.

Newton’s Second Law of Motion: The rate of change in momentum of a body is directly proportional to the applied force on the body and takes place in the direction of force.
If F=Force applied, a= Acceleration produced and m= Mass of body, then F=ma.

Newton’s Third Law of Motion: To every action, there is an equal and opposite reaction.
Example: Example of Third Law: 1. Recoil of a gun 2. Motion of Rocket 3. Swimming 4. While drawing water from the well, if the string breaks up the man drawing water falls back.