The blades of a fan turn at 1250rpm at low speed. When the fan is switched to high speed, the rotation rate increases uniformly to 1750rpm in a period of 3.0sec.

What is the average angular acceleration of the blades, in rad/sec^2?

How do I convert rpm to rad/sec?

XXXrpm= XXXrev/min *1min/60sec*2PIrad/rev