A girl travels along a straight road for the first half time with a velocity 4m per sec and the second half time with a velocity of 2m per sec. The mean velocity is given by is???
Answers
Given that, a girl travels along a staright road for the first half time with a velocity of 4 m/s and the second half time with a velocity of 2 m/s.
There are two cases in this question, in first half the girl travels with a velocity of 4 m/s and in the second half travels with a velocity of 2 m/s.
We have to find the mean velocity of the girl.
Let us assume that the girl is travelling with a time 't'.
For first half:
Distance (d1) = Speed (velocity) × Time
d1 = 4 × t ................(1st equation)
For second half:
Distance (d2) = Speed × Time
d2 = 2 × t .................(2nd equation)
Total distance travelled by girl = d1 + d2
= 4t + 2t = 6t
Total time taken by girl = t + t = 2t
Now,
Mean velocity = (d1 + d2)/2t = 6t/2t = 3 m/s
Therefore, the mean velocity of the girl is 3 m/s.