We see many objects around us, some of them are at rest, and some of them are moving.
What causes the objects to move?
When you get up from the school desk, you are pushing yourself against it. While entering into the home, you always push or pull the closed door with your hands. In a cricket match, you apply force on the ball by using the bat to hit a boundary. In order to win the game, you need to apply more force on the bat to get more fours and sixes. It is only then you could win the game.
So, to move an object which is actually at rest, we need a force.
What is 'rest'? What is 'motion'?
When there is a change of position of an object with respect to time, then it is called motion, if it remains stationary, it is called rest.
A man applies force to open the door
A baseball player hits a ball by applying force
A push or pull that changes the position, size, shape and speed of the moving body is called force. It can also change the direction of the moving body. It is measured in terms of \(newton\).
Actions like picking, opening, closing, kicking, hitting, lifting, flicking are often used to describe specific tasks. Each of these actions usually results in some change in the state of motion of an object. i.e. By doing any one of these activities creates a force on the object.
Force can
  • Change the states of the body from movement to rest.
  • Change the states of the body from rest to movement.
  • Alter the speed of the object.
  • Change the shape of the object.
  • Change the direction of the movement.