Newton first law:
A body continues in its state of rest or of uniform motion in a straight line provided no net force acts on it.
Explanation for rest:
Similarly Newton's first law of motion deals with bodies which are either at rest or moving with uniform speed in straight lineAccording to first law of motion, a body at rest remains at rest provided no net force on it .thispart of the law is true as we observe that objects do not move by themselves unless some moves it.
Explanation for motion:
Similarly a moving object does not stop moving by itself. A ball rolled on a rough ground stops earlier than that rolled on smoothground. It is because rough surface offer greater friction. If there would be no force of oppose the motion of the body would never stop
Newton's Second Law of Motion:
When a net force acts upon a body, it produces as acceleration in the body in the direction of force and the magnitude of acceleration is directlyproportional to the net force and is inversely proportional to the mass of the body.
If the force f is acting on the body of mass m then we can write this in the mathematical form is as
a x f _______>(1)
a x 1/m _____> (2)
From (1) and (2) we have
a x F/m
a = Constant x F/m
a = k x F/m
In the above equation according to the international system units if m= 1kg
a = 1ms-²,F= 1N then the value of k will be 1. So the equation can be written as