__MOTION__

When a body changes its position continuously with respect to a stationery object, which is taken as a reference point. It can be depicted by this graph:

Motion includes both distance and displacement.

**Distance** is a scalar quantity because it has magnitude only.

**Displacement** is a vector quantity because it has both magnitude and direction.

__TYPES OF MOTION__

There are 2 types of motion:

__UNIFORM MOTION__

An object shows uniform motion if it travels equal distance in equal interval of time. It can be depicted by this graph:

__NON UNIFORM MOTION__

An object is said to be in non uniform motion if it covers unequal distance in equal interval of time. It can be depicted as:

**NOTE**: The motion of freely falling body is an example of non-uniform motion. Non-uniform motion is also known as accelerated motion.

__SPEED__

Speed of a body is the distance travelled by it in per unit time.

The formula to calculate is:

Speed (v) = Distance (s) / Time(t)

S.I. Unit for speed = metre/sec or m/s

Speed is a scalar quantity.

__VELOCITY__

Velocity of a body is the distance travelled by it in per unit time in given direction. It can also be defined as speed in a specific direction.

It can be calculated as:

V = s / t

Where, v is the velocity, s is the distance and t is the time.

Velocity is a vector quantity.

If 2 types of velocity are given in the question as initial and final velocity, then average velocity is calculated as-

Average velocity= Initial velocity + Final velocity/2

__ACCELERATION__

Acceleration is the change in velocity of a moving body with time. It can be calculated as:

Acceleration= Change in velocity/ Time taken

Or, A= v-u/t

Where, v= final velocity, u= initial velocity and t= time

S.I. unit= ms^{-2}

Acceleration is a vector quantity and when a body is moving with a uniform velocity, its acceleration will be zero

It is of 2 types:

__1.UNIFORM ACCELERATION__

When acceleration increases at equal amount in equal amount of time, it is known as uniform acceleration.

__2.NON UNIFORM ACCELERATION__

When acceleration increases at unequal amount in equal amount of time, it is known as non uniform acceleration.

Q.1. Motion includes:

a. Distance

b. Displacement

c. Both

d. None

**Ans. c**

Q.2. What is the SI unit of speed:

a. cm sec-1

b. met sec-1

c. km sec-1

d. met min-1

**Ans. b**

Q.3. What is the formula to calculate the speed:

a. v= s/t

b. v= t/s

c. s= s/t

d. s=t/s

**Ans. a
**

Q.4. A train has covered 2000metres in a minute. Calculate the speed.

a. 33.33 m/s

b. 33.43 m/s

c. 50 m/s

d. 34.43 m/s

Q.5. Speed is a:

a. scalar quantity

b. vector quantity

c. mixed quantity

d. None

Q.6. Velocity is a:

a. scalar quantity

b. vector quantity

c. mixed quantity

d. None

**Ans. a
**

Q.7. If a train was moving with a initial velocity of 50 m/s and final velocity of 85 m/s. Calculate the average velocity of the train.

a. 67.5 m/s

b. 77.5 m/s

c. 50 m/s

d. 67 m.s