__DISTANCE__

It is the total length travelled by a body in its course of journey.

__Characteristics of distance are:__

- It is a scalar quantity.
- In CGS system, its unit cm (centimeter).
- In MKS system, its unit is m (meter).

__DISPLACEMENT__

The shortest distance between the initial and the final states of a body in its journey measured in a particular direction.

__Characteristics of displacement are:__

- It is a vector quantity.
- DISTANCE and DISPLACEMENT have same units.
- In CGS system, its unit cm (centimeter).
- In MKS system, its unit is m (meter).

__DIFFERENCE BETWEEN DISTANCE AND DISPLACEMENT__

If a body travels in a straight line, the distance and displacement will be equal.

However, if it does not then it can be explained with the help of following figure:

In the above figure, the curved distance from point A to B is the actual **distance** covered by the body and the shortest distance between A and B shown by a straight line is known as **displacement**.

__SPEED__

The rate of change of distance of a body in its journey is called speed

__Characteristics of speed are:__

- It is a scalar quantity.
- Its formula is, speed= distance/ time
- In CGS system, its unit is cm/sec.
- In MKS system, its unit is m/sec.

__VELOCITY__

The rate of change of displacement of a body in its journey is called velocity.

__Characteristics of velocity are:__

- It is a vector quantity.
- Speed and velocity have same units.
- In CGS system, its unit is cm/sec.
- In MKS system, its unit is m/sec.

__DIFFERENCE BETWEEN SPEED AND VELOCITY__

Suppose A body started moving in a circular direction from point A and covered the entire perimeter of 500 m in 20 sec and reached finally to the same origin point. Then speed will be calculated as

Speed= 500/20 = 25 m/sec

But, its velocity will be 0 as there is no change in the displacement and the initial point and the final point are the same. Thus, change in displacement will become 0 as a result velocity will become **zero.**

__ACCELERATION__

The rate of change of velocity of a body during its journey is called acceleration.

__Characteristics of Acceleration are:__

- Acceleration, a= change of velocity/ time
- When a body is moving with uniform velocity, then its acceleration will be zeto.
- In CGS system, its unit is cm/sec
- In MKS system, its unit is m/sec
^{2} - It is a vector quantity.

Q.1. A bike accelerates uniformly from rest to a speed of 7.10 m/sec over a distance of 35.4 m. Determine the acceleration of the bike.

- 0.712 m/sec
^{2} - 0.711 m/sec
^{2} - 0.710 m/sec
^{2} - 0.600 m/sec
^{2}

Ans. a

Q.2. A car takes 4 hours to cover a distance, if it travels with a speed of 40 mph. What should be its speed to cover the same distance in 1.5 hours:

- 106.66 mph
- 107 mph
- 106 mph
- 107.5 mph

Ans. a