Question

9) A boy goes from 2 m to 12m mark and back to 10m mark in 3 second its
average speed is:
[2003 PM]
* 2 in /s
* 6 m/s
* 4 m/s
* Zero
​

Answer 1

Answer:

4 m/s

Explanation:

In first go:

Distance = 12 m - 2 m = 10 m

In second:

Distance = 12m - 10m = 2m

Total distance = 10m + 2m = 12m

Total time taken = 3 sec

Therefore,

Average speed is 12m/3 sec = 4 m/s

Answer 2

Answer:

c) 4 m/s

Explanation:

A boy goes from 2 m to 12m mark and back to 10m mark in 3 second.

Case 1)

Distance covered = Final distance - Initial distance

= 12 m - 2 m

= 10 m

Case 2)

Distance covered = Final distance - Initial distance

= 12m - 10m

= 2m

Total distance covered = Distance covered in 1st case + 2nd case

= 10m + 2m

= 12m

Also given that, total time taken is 3 sec.

Now,

Average speed = (Total distance covered)/(Total time taken)

= 12m/3 sec

= 4 m/s

Hence, the average speed is 4 m/s.