KinematicsHard
Question
A student is standing at a distance of 50 meter from the bus. As. the bus begins its motion with an acceleration of 1 ms-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
Options
A.8 ms-1
B.5 ms-1
C.12 ms-1
D.10 ms-1
Solution

Let the student travels distance s1 in time t and catches the bus.
s1 = ut ......(1)
Distance traveled by the bus in time t
s2 = 0 +
at2 ......(2)The student is able to each the bus if.
s1 = d + s2
ut = d +
1 × 12or, t2 - 2ut + 2d = 0
Solving the quadratic equation
t = - 2 ±

= - 2 ± 2

For t to be real
u ≥

≥
= 10m/s.Create a free account to view solution
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