A magnetic computer disk 8.0 cm in diameter is initially at rest. A small dot is painted on the edge of the disk. The disk accelerates at 600 rad/ s^2 for 1/2 s, then coasts at a steady angular velocity for another 1/2 s . a) What is the speed of the dot at t = 1.0 s? b)Through how many revolutions has it turned? for a) i kept getting the answer wrong: i did : d=8.0cm so r=4.0 cm ti=0s tf=0.5s a=600 rad/s^2 vi=(2)(pi)(4.0cm) / 1.0s so; vi=25m/s and for part b) i think you have to use the kinematic equation after you get vi.. i'm not sure tho.. am i right?? please help. thanks in advance!