How Is the Average Power Output Calculated for an Airplane Propeller?

[mcchoy528]

Homework Statement

An airplane propeller is 2.78 m in length (from tip to tip) and has a mass of 127 kg . When the airplane's engine is first started, it applies a constant torque of 1880 N⋅m to the propeller, which starts from rest.
Part D
What is the average power output of the engine during the first 5.00 rev ?

Known:α=23.0rad/s²
ω after making 5.00rev=38.0rad/s
Work done by engine during first 5 rev=5.91kJ

Homework Equations

P_av= Work done/time
θ=ω₀t +1/2αt²

The Attempt at a Solution

Since ω₀=0,
θ=1/2αt²
t= √(2*5*2π/38.0)=1.65s
P_av= 5.91/1.65=3.58kW

I don't know why my answer is incorrect. Can anyone help?

 

[mjc123]

Where do the "knowns" come from? Are you told this in the question? Where does the "work done during first 5 revs" come from? This is wrong. How is the work calculated?
In your equation for t, I think you've put ω instead of α in the denominator.