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explain speed,distance,displacement,speed,velocity,acceleration,retardation using animations(by video)

Distance is a scalar quantity  while displacement is a vector quantity but both having the same dimension (L) and unit metre(m).

The magnitude of the displacement of an object between two points is the shortest distance between those two points.

For a moving particle distance  can never be zero or negative while displacement can be zero, positive or negative.

For a moving particle distance can never decrease with time while displacement can. Decrease in displacement with time means  that the body is moving towards the initial position.

Speed of a body is the distance traveled by it per unit time, ie, Speed = 

If a body travels a distance s in time t, then its speed v is given by :

                              v = s/t

        where      v = speed

                        s = distance traveled

              and     t = time taken (to travel that distance)

Velocity of a body is the distance traveled by it per unit time in a given direction.  The SI unit of velocity is same as that of speed, namely, meters per second (m/s or ms^-1 ).

Acceleration of a body is defined as the rate of change of velocity with time.

ie., Acceleration   = change in velocity / Time taken for change

Change in velocity is the difference between the final velocity and initial velocity.

Suppose the initial velocity of a body is 'u' and it changes to a final velocity ' v' in time t, then:

                          where

a is the acceleration of the body

v is the final velocity of the body

u is the initial velocity of the body

The SI unit of acceleration is meter per second per second or m / s². Acceleration is a vector quantity.

Acceleration takes place when the velocity of a body changes. The velocity of a body may increase or decrease, accordingly the acceleration is of two types- positive acceleration and negative acceleration. If the velocity of a body increases, the acceleration is positive and if the velocity of a body decreases, the acceleration is negative. Negative Acceleration is also known as Retardation or Deceleration.

Retardation is measured in the same way as acceleration, that is retardation is equal to  and has the same units of acceleration ( "m ? s²).

Example : Train comes to rest at the station.