A car of mass 800kg attains a speed of 25m/s in 20 secs. The power developed in the engine is
-
A.
1 . 25 x 104 W -
B.
2 . 50 x 104 W -
C.
1 . 25 x 106W -
D.
2 . 50 x 106 W
Correct Answer: Option B
Explanation
Power = Force x (frac{distance}{time}) = (frac{m(v – u)}{t} times v)
(frac{800(25 – 0)}{20} times 25)
= 2.5 x 10(^{4}) watts