Question

What is meant by the term average speed?

Answer 1

Hint: We know that speed is the measure of how fast an object moves with respect to some other object. there are two types of speed namely the instantaneous speed and the average speed, both vary from each other in very small ways, as discussed below.

Complete step-by-step solution:
Speed is a scalar quantity which has only magnitude and not direction. We know that a speed is the change in the distance with respect to time. This implies that if the speed of the object is high, then it is moving fast, whereas if the speed of the object is low, then it is moving slowly.
Clearly, speed depends on time. Then we can classify speed into average speed and instantaneous speed based on time.
We know that speed is the change of distance with respect to time, and is given by $\text{Speed}=\dfrac{\text{Distance}}{\text{Time}}$
Average speed is the change in distance $d$ over a period of time $t$, and is given as $u_{avg}=\dfrac{d}{t}$
If a body covers a distance , say $s$ during the interval of time $t_1$ to $t_2$ then the average speed $u$ of the body is given as
$u=\dfrac{s}{t_1-t_2}$
Whereas, instantaneous speed is the small distance $d\;s$ covered during a small period of time $d\;t$. It is denoted using calculus and is given as $u_{inst}=\dfrac{ds}{dt}$

Note: Both velocity and speed measure how fast an object moves. But there is a small difference between velocity and speed. Velocity is a vector quantity which has both direction and magnitude, unlike speed which is a scalar quantity and can have only magnitude and not direction. This is one major difference between the both, and it is a physical quantity.