Newton’s second law of motion

## What is the second law of motion?

Newton’s second law of motion deals with situations when a** net force** is acting on a body.It states that:

“When a net force acts on a body,it produces acceleration in the body in the direction of the net force.The magnitude of this acceleration is directly proportional to the net force acting on the body and inversely proportional to its mass.”

If a force produces an acceleration **a** in a body of mass m,then we can state mathematically that as:

a ∝ F

and a ∝ 1/m

or a ∝ F/m

or F ∝ ma

Putting k as proportionality constant we get

F= kma …..(1)

In SI units ,the value of k comes out to be one.Thus equation (1) becomes:

F =ma

SI unit of force is newton (N).According to newton’s second law of motion:

“One newton (1N) is the force that produces an acceleration of 1ms^{-2} in a body of mass of 1 kg.Thus,a force of one newton can be expressed as:

1N = 1kg ×1ms^{-2}

or 1N =1kgms^{-2}