# What is Frame Of Reference- Newton’s Law of motion

Frame Of Reference

Frame of reference is a system to measure position and motion of different bodies. The system consist of direction and a time machine.

There are two types of frame of reference

a. Inertial frame of reference

b. Non inertial frame of reference

Inertial Frame Of Reference:

a. Frames of reference in which Newton's Laws of motion are applicable are called inertial frame.

b. Inertial frames of reference are either at rest or move with uniform velocity with respect to a fixed imaginary axis.

c. In inertial frame, acceleration of a body is caused by real forces.

Examples:

1) A lift at rest.

2) Lift moving up or down with constant velocity.

3) Car moving with constant velocity on a straight road.

Non- Inertial Frame Of Reference:

a. Frames of reference in which Newton's Laws are not applicable are called non-inertial frames.

b. Accelerated frames mave with either uniform acceleration or non uniform acceleration

c. All the accelerated and rotating frames are non- inertial frames of reference.

Examples:

1) Accelerating car on a road.

2) Merry go round.

3) Artificial satellite around the earth.

Apparent weight in a lift (elevator).

a.When lift is stationary or moving with uniform velocity then acceleration is zero.

N=mg. Weight not change.

b. When lift is moving upward with an acceleration (a) then weight increase.

N-mg=ma

N=mg+ma

N= m(g+a) weight increase.

c.When lift is moving downward with an acceleration (a) then weight decrease.

N+mg=ma

N= mg-ma

N= m(g-a). Weight decrease.