Newton enunciated following three laws of motion:-
First law:- A body continues to be in the state of rest or of uniform motion unless an external force is applied on it. This law is also known as law of inertia.
Example:-
- If you slide a hockey puck on ice, eventually it will stop, because of the friction on the ice. It will also stop if it hits something, like a player's stick or a goalpost.
- If you are driving in your car at a very high speed and hit something, like a brick wall or a tree, the car will come to an instant stop, but you will keep moving forward. This is why cars have airbags, to protect you from smashing into the windscreen.
Second law:- The rate of change of momentum of a body is directly proportional to the force applied on it and is in direction in which the force is applied.
Example:-
- If you use the same force to push a truck and push a car, the car will have more acceleration than the truck, because the car has less mass.
- It is easier to push an empty shopping cart than a full one, because the full shopping cart has more mass than the empty one. This means that more force is required to push the full shopping cart.
Third law:- To every action, there is an equal and opposite reaction.
Example:-
- When air rushes out of a balloon, the opposite reaction is that the balloon flies up.
- When you dive off of a diving board, you push down on the springboard. The board springs back and forces you into the air.
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