Reference body

1. MOTION

2. REFERENCE BODY
An object with respect to
which the state of rest or
motion of an object is
described.

3. STATE OF MOTION
If the position of an object
changes with respect to the
reference body.

4. eg:
1. A person in a moving bus
with respect to the road.
2. A crow on eagle’s back with
respect to the ground.

5. STATE OF REST
If the position of an object
doesnot change with respect
to the reference body.

6. eg:
1. A person in a moving bus
with respect to the bus.
2. A crow on eagle’s back
with respect to the eagle.

7. DISTANCE
The length of the path
travelled by an object.
Unit is metre.
It is a scalar quantity.

8. DISPLACEMENT
The straight line distance
between the initial position
and final position.
Unit is metre.
It is a vector quantity.
“Displacement will always less
than the distance”.

9. SPEED
The distance travelled in
unit time.
Unit is m/s.
It is a scalar quantity.

10. VELOCITY
The displacement in unit time.
Unit is m/s.
It is a vector quantity.

11. UNIFORM SPEED
If a body covers equal
distance in equal intervals
of time.

12. NON-UNIFORM SPEED
If a body covers unequal
distances in equal interval
of time.

13. UNIFORM VELOCITY
If the body cover equal
distances in the same
direction in equal intervals of
time.
Eg. The propogation of light in
vaccum.

14. NON-UNIFORM VELOCITY
If there is any change in speed
or direction or both of a
moving body.
Eg. Motion of a freely falling
body.

15. ACCELERATION
Rate of change of velocity.
Unit is m/s².
It is a vector quantity.

16. RETARDATION
The rate of decrease in the
velocity .
Retardation= -Acceleration