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Unit of speed

Speed formula - Distance travelled (s)/Time (t)

Unit of speed

SI unit of speed is m s-1 CGS unit is cm s-1
Since distance travelled is a scalar, the speed of a particle is also a scalar.

Instantaneous Speed

The speed of a particle at a given instant is known as instantaneous speed. The speedometer of a vehicle indicates the instantaneous speed of the vehicle.
 
Uniform Speed: A body or particle is said to possess uniform speed if it travels equal distances in equal intervals of time.
Consider a person travelling from A to B through O. If he walks at a constant rate of 1 m s-1 , i.e., for every 1 s if he travels 1 m, then the person is said to possess uniform speed. Uniform speed indicates that the instantaneous speed of particle remains the same throughout the motion.
Variable speed: If the instantaneous speed of a particle changes with time, then the body is said to be moving with variable speed.

Average Speed

Average speed: Defined as the ratio of the total distance travelled to the total time taken by the particle to cover that distance.
Average speed formula = Total distance/Total time
Velocity: It is displacement of a body in unit time or rate of displacement.
Velocity formula = displacement/time
Velocity is a vector quantity. SI unit of velocity is m s-1 and or C.G.S. unit of velocity is cm s-1 .
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