A bus starts to move with an acceleration of 1m/s^2
.A man who is 48m behind the bus runs with constant velocity of10m/s to catch it.In hhow much time he will catch the bus?

a)6sec b)8sec c)10sec d)12sec

Question

A bus starts to move with an acceleration of  1m/s^2
.A man who is 48m behind the bus runs with constant velocity of10m/s to catch it.In hhow much time he will catch the bus?

a)6sec     b)8sec    c)10sec       d)12sec

anonymous · Answer

The answer is b) 8 seconds.

You just have to try plugging the choices into the relative equations, and whatever works is the right answer. For b) 8 seconds, it is:

a=1m/s^2

Bus displacement:
x=0.5at^2
x=0.5t^2
x=0.5(64)
x=32 (after acceleration).
Plus the fact it's already 48m ahead of the man, so it's x location would be:
32+48= 80m

Man displacement:
x=vt
x=10*8
x= 80m

So they'll both be at the same place after 8 seconds.