A student is standing at a distance of 50 metres from the bus. As soon as the bus begins its motion with an acceleration of 1ms–2, the student starts running towards the bus with a uniform velocity u. Assuming the motion to be along a straight road, the minimum value of u, so that the student is able to catch the bus is 

(1) 5 ms–1

(2) 8 ms–1

(3) 10 ms–1

(4) 12 ms–1

Concept Videos :-

#45-Relative motion
#46-Relative motion-1
#47-Relative motion-2
#48-Relative motion-3
#49-Relative motion-4
#50-Relative motion-5

Concept Questions :-

Relative motion in 1-D

(3) Let student will catch the bus after t sec. So it will cover distance ut.

Similarly distance travelled by the bus will be 12at2 for the given condition

ut=50+12at2=50+t22 [a=1m/s2

u =50t+t2

To find the minimum value of

dudt=0, so we get t=10sec, then u=10m/s  

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