Newton's Law of Motion

There are three laws of motion ass originally enunciated by Sir Isaac Newton (1642-1727 A.D).

First Law: Everybody continues in its state of rest or of uniform motion in straight line unless an unbalanced force acts on it.
Examples:

• When we shake a mango tree, the mango fall down
• A man getting out of a moving bus or train falls in the forward direction.
• Abullect fired on a window glass pane makes a clear hole in it without causing cracks
• The blades of a fan continue to rotate for some time when the current is switched off

Second Law: Acceleration produced in a body is directly proportional to the force applied to it and inversely proportional to its mass. The motion takes in the direction of the force.
Examples:

• A cricket player while catching a ball, moves his hands backwards.
• A person falling on a cemented floor is injured more than falling on a sandy floor or mattress
• It is difficult to catch a cricket ball as compared to a tennis ball moving with the same velocity

Third Law: To every action there is an equal and opposite reaction.
Example:

• In order to swim a man pushes water backwards with his hands. Due to the reaction offered by water to the man, the man is pushed forwards.
• It is difficult to walk on slippery ground or sandy surface. This is because we are unable to push the ground sufficiently hard. Consequently, reaction is not sufficient to help us to walk
• Birds, while flying, push air with their wings. The air exerts an equal and opposite force on the birds and that force causes birds to move forward.