Posted by Alex on .
A student puts on a Dresden Dolls disc in her cd player which spins at 1800 revolutions per minute. A compact disc has a mass of about 0.016 kg and a radius of 6.0 cm.
a) What is the period of rotation in seconds?
b) What is the frequency of the rotating disc?
c) What is the angular speed of the disc?
d) What is the linear speed of a scratch on the outer edge of the disc?
a. T=1min/1800rev=60s/1800rev=0.0333 s.
b. F = 1/T = 1/0.0333 = 30 cy/s = 30 Hz.
c. Va=30cy/s * 6.28rad/cy=188.84 rad/s.
= Angular velocity.
d. C = pi*2r = 3.14*12 = 37.7 cm = 0.377 m = The Circumference.
V = 30cy/s * 0.377m/cy = 11.3 m/s.