Question

If a body starts from a point and returns back to the same point, then it's.

• A. average speed is zero, but average velocity is not zero.
• B. both average speed and average velocity are zero.
• C. average speed and velocity depend upon the path.
• D. average velocity is zero, but not the average speed.

Answer 1

The correct option is D

average velocity is zero, but not the average speed.

Step 1:

Let us consider the body moves from point A to B.

After reaching B, the body returns to the initial point A.

So, the initial point is equal to the final point.

X is the distance between A and B.

T be the total time taken to complete the distance from the initial point to the final point.

Average speed :

Average speed is defined as the total distance traveled by an object per total time taken.

$Averagespeed=\frac{totaldis\tan ce}{totaltime}$

$Averagespeed=\frac{X+X}{T}$

So, the average speed is not equal to Zero.

Average velocity:

Average velocity is defined as the total displacement of the object per total time taken.

$Averagevelocity=\frac{totaldisplacement}{totaltime}$

1. Displacement is the shortest distance between the initial point and the final point.
2. since the initial point is equal to the final point.
3. The displacement = 0.

$Averagevelocity=\frac{0}{T}=0$

So, If a body starts from a point and returns back to the same point, then the average velocity will be zero, but not the average speed.

Hence,

Option (d) is correct.