Question

A sports car accelerates from 0 to 30 mph in 1.5 s. How long would it take to accelerate from 0 to 60 mph, assuming the power of the engine to be independent of velocity and neglecting air drag?

Answer 1

Answer:

6 s

Explanation:

given,

Sports car accelerate from 0 to 30 mph in 1.5 s

time taken to accelerate  0 to 60 mph = ?

The power of the engine is independent of velocity and neglecting friction

power =

P = constant  

the kinetic energy for 60 mph larger than this of 30 mph

 = $\dfrac{\dfrac{1}{2}mv_1^2}{\dfrac{1}{2}mv_2^2}$

 = $\dfrac{v_1^2}{v_2^2}$

 = $\dfrac{60^2}{30^2}$

 = 4

gain in kinetic energy  = P x t

time = 4 x 1.5

       = 6 s