If a CD spins at 75 revolutions per minute, long, in seconds, does it take for the CD to rotate through an angle of 1125 ?

Answer 1

75 rev/min.

V = (75 / 60) rev/s * 360 deg/rev = 450
deg/s.

t = 1125 deg / 450 deg/s = 2.5 Seconds.