Motion in a Straight Line - Result Question 33
34. A bus is moving with a speed of $10 ms^{-1}$ on a straight road. A scooterist wishes to overtake the bus in $100 s$. If the bus is at a distance of $1 km$ from the scooterist, with what speed should the scooterist chase the bus?
(a) $40 ms^{-1}$
(b) $25 ms^{-1}$
(c) $10 ms^{-1}$
(d) $20 ms^{-1}$
[2009]
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Answer:
Correct Answer: 34. (d)
Solution:
- (d) Let $v$ be the relative velocity of scooter w.r.t bus as $v=v_S-v_B$
$v=\frac{1000}{100}=10 ms^{-1} V_B=10 ms^{-1}$
$\therefore \quad v_S=v+v_B$,
$ =10+10=20 ms^{-1} $
$\therefore \quad$ velocity of scooter $=20 ms^{-1}$
When two bodies are moving in same directions, relative velocity is between difference individual velocities.
$ \vec{V} _{A B}= \vec{V} _A- \vec{V} _B $
