I need help with one of my last hw problem can you help me?

Question

A magnetic computer disk with a 4.03 cm radius is initially at rest. A small dot is painted on the edge of the disk. The disk accelerates at 500 rad/s2 for 1.76 s. How many revolutions has the dot completed during this time interval?

Thank you

Answer 1

first, how many radians?
radians = (1/2) a t^2 = 250 (1.76)^2
= 774.4 radians

revolutions = radians/2 pi = 123 revs