Question

A body moving along a straight line traversed one third of the total distance with a velocity 4
m/sec in the first stretch. In the second stretch the remaining distance is covered with a
velocity 2 m/sec for some time t0 and with 4 m/sec for the remaining time. If the average
velocity is 3 m/sec.

(i)Find the time for which body moves with velocity 4 m/sec in second stretch.

Find the range of average velocity (m/sec) for which the journey of the body as described, is
possible.
Ans
(i)
t0/2
(ii) 4.0m/s > v av > 2.4m/s

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Answer 1

Answer:

`(3)/(2)t_(0)`

`t_(0)`

`2t_(0)`

`(t_(0))/(2)`

Answer :

D

Solution :

Sol: `t_(1)=(s//3)/(4)=(s)/(12)`

`(2s)/(3)=2(t_(0))+4(kt_(0))=t_(0)(2+4k)ort_(0)=(2s)/(3(2+4k))`

`"Average velocity"=(s)/(t_(1)+t_(0)+t_(0)k)`

`=(s)/((s)/(12)+(2s(1+k))/(3(2+4k)))=(6(2+4k))/((5+6k))`

`V_(av)(5+6k)=12+24k` gives `k=(1)/(2)`

Required time `=kt_(0)=(t_(0))/(2)`

Explanation: