# Motion

A body is said to be motion when it changes its postion continuously with respect to a stationary object. Type of motion:

**Uniform Motion:**A body has a uniform motion if it travels equal distances in equal intervals of time.**Non-Uniform Motion:**A body is said to be in non-uniform motion if it travels unequal distances in equal intervals of time

## Distance

The actual length of path, travelled by a moving body without considering its direction is known as it Distance.

## Displacement

When a body moves from one position to another, the shortest distance between the initial point and the final point of the body is known as its displacement.

## Speed

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

Speed = Distance Travelled / Time Taken.

The SI unit of distance is metre(m) and that of time is second(s), therefore, the SI unit of speed is meters per second which is written as m/s or ms-1

## Average Speed

The average speed of a body is the total distance travelled divided by the total time taken to cover this distance

Average speed = Total distance travelled / Total time Taken

## Uniform Speed(Constant Speed)

A body has a uniform speed if it travels equa distances in equal intervals of time.

## Velocity

Velocity of a body is the distance travelle by it in per unit time in a given direction.

Velocity = Distance travelled in a given direction / Time Taken.

v=s/t,

where v= velocity of the body, s= distance travelled(in the perticular direction), t=time taken to travell that distance

## Uniform Velocity (Constant Velocity)

A body has a constant velocity if it travels in a straight line and moves over equal distances in equal intervals of time in a perticular direction.

We can change the velocity of body can be changed by the speed of the body or keeping the speed constant but by changing the direction.

## Average Velocity

Average velocity is the sum or intial and final velocity and divide it by 2.

Average Velocity = (Initial Velocity + Final Velocity)/2.

## Acceleration

The rate of change of velocity of a body with time is known as acceleration

Acceleration = Change in velocity / Time taken for change.

and, Change in velocity = final velocity-initial velocity.

Therefore, Accerelation = (Final velocity-Intial velocity)/Time Taken,

a=(v-u)/t, SI unit of acceleration is m/s2

## Uniform Acceleration

A body is said to be in uniform acceleration if it travels in a straight line and its velocity increases equal amount in equal intervals of time

## Non - Uniform Acceleration

A body has a non-uniform acceleration if its velocity increases by unequal amounts in equal intervals of time.

## Retardation (Negative Acceleration)

When the velocity of a moving body decreases with time while travelling in a straight line then the acceleration of the body is said to be negetive. Negative acceletation is also called as retardation.

## Circular Motion

When a body moves arount a fixed foint ia a circular path with uniform speed, tis motion is calleed as uniform circular motion. Circular motion is accelerted even though the speed of the body remains constant since the direction of motion changes contineously

## Force

A force is an external pressure which tends to change a stationary body into motion or makes to change the speed and direction of a moving body or change the shape of the body.