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The air resistance to a car at 20 kmph is R. The air resistance at 40 kmph will be
- AR
- B2R
- C4R
- D4R²
Correct answer: C
Discussion 1
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0
CCommunity
4R
R = K.A.V2 when vehicle speed is about 20km/hr.
Where K = Co-efficient of air resistance.
A = Projected area of vehicle.
V = Vehicle speed in km/hr.
When vehicle speed is about 40km/hr, speed is doubled so we can write V=2V,
Therefore, R = K.A.(2V)2.
R = K.A.4V2.
R = 4K.A.V2.
R= 4R
R = K.A.V2 when vehicle speed is about 20km/hr.
Where K = Co-efficient of air resistance.
A = Projected area of vehicle.
V = Vehicle speed in km/hr.
When vehicle speed is about 40km/hr, speed is doubled so we can write V=2V,
Therefore, R = K.A.(2V)2.
R = K.A.4V2.
R = 4K.A.V2.
R= 4R