A force is a push or pull on an object resulting the object's interaction with the other object.

4 effects of force are:
1. Force can change the shape of the object. Eg. force applied on rubber band can change its shape to another shape.
2. Force can change the motion of the object. Eg. if a ball is moving and we applied a hand on it it will move slowly. So force changes the speed of the object.
3. Force can make a stationary object to move. Eg. when we kick a ball, we applied force on the ball causing it to move from the stationary positions.
4. Force can make a moving object stationary. Eg. when a moving ball comes and we put hand in front of it , it stops thereby making it stationary.
Force is a push or pull which causes motion. 1 force is the product of mass and accelration 2 its SI unit is Newton