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A rocket rises vertically up from the su...

A rocket rises vertically up from the surface of earth so that it is distance varies from the earth's surface as `l=bt^(2)` where 'b' is a constant. After `10 sec` the rocket has travelled `2 Km`. Determine it's speed at that moment.

A

`100 m//s`

B

`200 m//s`

C

`400 m//s`

D

`600 m//s`

Text Solution

Verified by Experts

The correct Answer is:
C
distance `=l=bt^(2)=2000`
velocity `=(dl)/(dt) =2bt=2t.((l)/(t^(2)))=400m//s`
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