Question

5.
1. A boy walks on a horizontal road and travels
25 km with constant speed of 5 kmh! Then he returns to
the same point and walks with constant speed of
7.5 km h-! What is the (a) average velocity of the man
during the whole journey. (b) average speed of the man
over the following intervals of time (i) 0 to 30 min, (ii) 0 to
50 min (iii) 0 to 40 min.
6.​

Answer 1

:Answer:

3)  a)0 b) 1)5  2)0.05  3)5.55

Explanation:

average velocity = displacement/time

  here displacement is 0 therefore average velocity is 0

average speed over the time intervals

average speed = total distance /total time

in the first case distance is 2.5 km

                          time is 0.5 hr , average speed = 5 kmph

in the second case distance is 4.16

                           time is 50 min = 0.83,average speed is 0.05

in the thrid case distance is 3.33

                           time is 40 min ,average speed is 5.55