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Comprehension # 4 When the mass of a s...

Comprehension # 4
When the mass of a system is variable, a thrust force has to be applied on it in addition to all other forces acting on it. This thrust force is given by : `vec(F) = vec(v)_(r) (+- (dm)/(dt))`. Here `vec(v)_(r)` is the relative velocity with which the mass `dm` either enters or leaves the system.

A car has total mass `50 kg`. Gases are ejected from its backwards with relative velocity `20 m//s`. The rate of ejection of gas is `2 kg//s`. Total mass of gas is `20 kg`. Coefficient of friction between the car and road is `mu = 0.1`.
Maximum speed of car will be `v = ....... m//s` :- (Take `ln ((4)/(3)) = 0.28` )

A

0.6

B

0.8

C

`1.0`

D

1.2

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Comprehension # 4 When the mass of a system is variable, a thrust force has to be applied on it in addition to all other forces acting on it. This thrust force is given by : vec(F) = vec(v)_(r) (+- (dm)/(dt)) . Here vec(v)_(r) is the relative velocity with which the mass dm either enters or leaves the system. A car has total mass 50 kg . Gases are ejected from its backwards with relative velocity 20 m//s . The rate of ejection of gas is 2 kg//s . Total mass of gas is 20 kg . Coefficient of friction between the car and road is mu = 0.1 . Car will start moving after time t = ......... s .

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