Instantaneous Speed Differ from Average Speed
How does instantaneous speed differ from average speed
Although the terms instantaneous speed and average speed
have similar definitions, but the two differ in the following respect
Differences between instantaneous speed and average speed
Instantaneous speed
1 Instantaneous speed is the distance travelled by a body
per unit time at a particular point of time (or in an infinitestimally small
interval of time)
2 Instantaneous speed of a moving object cannot be
calculated by using the formula s/t because, here ‘t’ should be immeasurably
small tending to zero.
Average speed
1 Average speed is the average distance travelled by a body
per unit time over a certain measurable interval of time.
2 Average speed can be calculated from the measured values
of distance and time.
Example – Arrange the following speeds in an increasing
order:
(a)
A bicycle moving with a speed of 18 km/h.
(b)
A fast runner with a speed of 7 m/s.
(c)
A car moving with a speed of 2000 m/min.
Soln :
Speeds of different moving bodies can be compared only when all these
are expressed in the same unit. Let us express all the speeds in the SI unit,
i.e, in ms-1
(a)
Speed of bicycle = 18 km/1h = 18x1000m/1x60x60s
= 18000m/3600s = 5 ms-1
(b)
Speed of a runner = 7m/s = 7 ms-1
(c)
Speed of car = 2000m/1min = 2000m/1x60s = 33.3 ms-1
The speeds in the increasing order are, 5 ms-1 ,
7 ms-1 , 33.3 ms-1 . This means, the speeds follow the order :
Bicycle, Fast runner, Car
i.e, 18 km/h, 7 m/s, 2000 m/min
Comments
Post a Comment