- #1
lpcampbe
- 15
- 0
A top fuel drag racer with a mass of 600.0 kg completes a quarter-mile (402 m) drag race in a time of 4.4 s starting from rest. The car's final speed is 115 m/s. What is the engine's average power output? Neglect friction and air resistance.
I know:
Power = Work/ change in time
W = Force * change in distance
F = mass * acceleration
Vf = Vi + at
so i solve for a
115 m/s = 0 m/s + a(4.4 s)
a = 26.1364 m/s^2
then i solve for F
F = 600 kg * 26.1364 m/s^2
F = 15681.8182 N
then i solve for W
W =15681.8182 N * 402 m
W = 6304090.909 J
then i solve for P
P = 6304090.909 J / 4.4 s
P = 1432747.934 W
I'm supposed to answer in kW
P = 1432.747 kW
I don't understand why this answer is wrong!
I know:
Power = Work/ change in time
W = Force * change in distance
F = mass * acceleration
Vf = Vi + at
so i solve for a
115 m/s = 0 m/s + a(4.4 s)
a = 26.1364 m/s^2
then i solve for F
F = 600 kg * 26.1364 m/s^2
F = 15681.8182 N
then i solve for W
W =15681.8182 N * 402 m
W = 6304090.909 J
then i solve for P
P = 6304090.909 J / 4.4 s
P = 1432747.934 W
I'm supposed to answer in kW
P = 1432.747 kW
I don't understand why this answer is wrong!