The fan blades of a jet engine in an airplane rotate counterclockwise with an initial angular velocity of 100 rad/s. As the airplane takes off, the angular velocity of the blades reaches 400 rad/s in 10 seconds. Calculate the average angular acceleration.

My answer is 30 rad/s however I've also seen 30 rad/s^2 Just want to verify the answer before I submit it, I'm attaching my work.

2 5 a - W - WO ( 400 - 100 40 0 = W = LOV = WO = - 20* + - to 10 - 0 300 0 = 7 8 - 30 radis 10 ATRO case-SEE-008 Tube.babu.arleo