Laws of Motion and Gravitation

Force is actually a push or pull which either changes or tends to change the state of rest or of uniform motion of a body.

It is very common which we all have observed that an object such as a chair lying in a room or vehicle part outside the house remains address unless push or pull is given to it. Such an object cannot move at its own.  In other words, a force has to be applied in order to move an object at rest. Also, if a body is moving along a straight line with some velocity, it is found that force is required to change the direction of motion or the magnitude of the velocity. In other words, force is an agent, which causes acceleration.

However, in certain cases, the acceleration caused by the force maybe practically zero. For example, if you push to a stationary track, it may not move. In such cases force merely tends to cause acceleration.

Hence, we can define the force as a push or a pull that produces or tends to produce motion in a body at rest; stops or tends to stop a body that is in motion; increases or decreases the magnitude of velocity of the moving body or changes the direction of motion of the moving body.