Question

define Newton's all three laws of motion

Answer 1

1. Newton’s first law of motion states that A body at rest or uniform motion will continue to be at rest or uniform motion until and unless a net external force acts on it.
It takes more effort or force to move a heavy mass. So its also known as law of inertia.

For Example :
A block is kept on the floor, it will remain at rest until we apply some external force to it. 

2. Newton’s second law of motion states that the net force experienced by a body is directly proportional to the rate of change of momentum of the body. 

F = ma   or      F = m dv/dt

3. Newton’s third law of motion, for every action, there is an equal and opposite reaction. 

For Example :
When you sit on a chair, your body exerts a force downward and that chair needs to exert an equal force upward or else the chair will collapse.


Also always remember these points

1. For 3rd law of motion : The force of action and reaction do not cancel each other because they act an different bodies.

2.There are consequences of Newton’s 2ndLaw of Motion.

a.) No force is required to move a body uniformly along a straight line.

In case of uniform motion the velocity remains the same through out the motion. Hence the acc. is zero

b.) Acceleration motion is always due to external force.

If no external force is applied then the body will continue to be in its state of rest or of uniform motion.

c.) It helps us to measure the force by using the equation.

F = ma   or      F = m dv/dt

d.) Concept of  Inertial Mass:
F = ma
a=F/m

So larger the mass smaller will be the acceleration produced in it by the force and hence greater will be the inertial.


#Happy_Learning!