Q. A car manufacturer claims that his car can be accelerated from rest to a velocity of $10\ ms^{- 1}$ in 5 s. If the total mass of the car and its occupants is 1000 kg, then the average horse power developed by the engine is
A) $\frac{10^{3}}{746}$
B) $\frac{10^{4}}{746}$
C) $\frac{10^{5}}{746}$
D) 8
Explanation
(b) $a = \frac{10 - 0}{5}ms^{- 2} = 2ms^{- 2};$
$F = ma$ or $F = 1000 \times 2$ N = 2000 N
Average velocity $= \frac{0 + 10}{2}ms^{- 1} = 5ms^{- 1}$
Average power $= 2000 \times 5\ W = 10^{4}\ W$
Required horse power is $\frac{10^{4}}{746}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.