CBSE
Class 10
Class 12
Speed is defined as the distance travelled by a body per unit time.
Thus,
The SI unit of speed is ms-1 whenever the distance covered by the body is expressed in metre and time in second.
A smaller unit of speed is cm s-1.
A larger unit of speed is km h-1.
Speed is a scalar quantity because it has only magnitude and no direction.
The speed of a body tells us how fast or how slow the body is moving. But it does not give the direction of motion.
Dimension formula : [M0L1T-1]
Speed can be two types uniform speed and non-uniform speed.
In uniform speed, a particle covers equal distances in equal intervals of time.
In non-uniform speed particle covers unequal distances in equal intervals of time.
Average speed:
Average speed is defined as the total path length travelled divided by the total time interval during which the motion has taken place.
Average Velocity:
Average velocity is defined as the change in position or displacement (∆x) divided by the time intervals (∆t).
where x2 and x1 are the positions of the object at time t2and t1, respectively.
The bar over the symbol for velocity is a standard notation used to indicate an average quantity. The SI unit for velocity is m/s or ms–1.