A top fuel drag racer with a mass of 500.0 kg completes a quarter-mile (402m) drag race in a time of 4.2s starting from rest. The car's final speed is 125m/s. What is the engine's average power output? Ignore friction and air resistance.

Answer 1

Divide the final kinetic energy by the time it takes to reach that velocity. That will be the average power and will have the dimensions of Watts.

You don't need to use the distance.
Acceleration was not constant during the interval, since the final velocity (125 m/s) was not twice the average (95.7 m/s)