Question

obtain information about Commonly used gadgets or divices which are based on the principles of newtons low of motion

Answer 1

Newton's second law states that the net force applied on a body is equal to the rate of change in  its momentum.

So, if the net force, F is zero, change in the value of v is be zero i.e., a body at rest will be at rest and a body moving with constant velocity will continue with the same velocity, until a net force is applied. This conclusion is similar to the Newton’s first law of motion