Question

`S_(1),S_(2)` and `S_(3)` are the different sizes of windows 1,2 and 3 respectively placed in avertical plane. A particle is thrown up in that vertial plane, find the correct options:
A. average speed of the particle passing the windows may be equal if `S_(1)ltS_(2)ltS_(3)`
B. average speed of the particle passing the windows may be equal if `S_(1)gtS_(2)gtS_(3)`
C. if `S_(1)=S_(2)=S_(3)`, the change in speed of the particle while crossing the windows will satisfy `DeltaV_(1)ltDeltaV_(2)ltDeltaV_(3)`.
D. if `S_(1)=S_(2)=S_(3)` the time taken by particle to cross the windows will satisfy `t_(1)ltt_(2)ltt_(3)`

Answer 1

Correct Answer - B::C::D
As going up, speed of the particle is decreasing and hence time taken in crossing the windows
(if `S_(1)=S_(2)=S_(3))` will be `t_(1)ltt_(2)ltt_(3)` since, `vecv=vecu+vec(a)t Deltaupropt` (as acceleration is same)
So, `Deltav_(1)ltDeltav_(2)ltDeltav_(3)` (as for equal windows `t_(1)ltt_(2)ltt_(3))` for unequal windows. `t_(1)=t_(2)=t_(3)` if `S_(3)ltS_(2)ltS_(1)`