A small bug with a mass of 8g is sitting on the edge of a vinyl record spinning at 25 revolutions per minute (rpm). The radius of the disc is 12 cm. What is the frictional force required to keep the bug in uniform circular motion?

Answer 1

25 revs/min = 25 * 2 * pi radians/ 60 seconds = 2.62 radians / sec
so
v = omega R = 2.62 rad/s * 0.12 meter = 0.314 meters/second
now you can do m v^2/R = mu m g or v^2/R = mu g