What is the net power needed to change the speed of a 1600-kg sport utility vehicle from 15.0 m/s to 40.0 m/s in 4.00 seconds

Work done = change in kinetic energy of vehicle

k.e. = ½mv²

So the k.e. of the vehicle changes from (½ * 1600 * 15.0²) = 180000 joules

to (½ * 1600 * 40.0²) = 1280000

That is an increase of (1280000 - 180000) = 1100000 joules = 1100 kJ

Power = energy / time

To supply that 1100 kJ of energy in 4.00 s therefore requires a net power of

(1100 kJ / 4.00 s) = 275 kW

Explanation:

okay i have so many questions. but the big one here is: um wt..f is this mess? ?

the answer is 12 as i may remember

: )