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An engine of a car of power 80 kW moves on a rough road with...

An engine of a car of power 80 kW moves on a rough road with a velocity of 32 ms-1. The forces required to bring it to rest is

A.

2.56 x 106N

B.

2.50 x 106N

C.

2.80 x 103N

D.

2.50 x 103N

Correct answer is D

In terms of dimension: power , P, = ML2T3
Force F1 = MLT-2; Vel, V, LT-1
From the above, => P = F x V
i.e, ML2T-3 = MLT-2 x LT-1
ML2T-3
=> 80,000 = F x 32

∴ F = 80,000
32

= 2500N
= 2.50 x 103N