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: Option D
Explanation
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