Question

A CD has a diameter of 12.0 cm. If the CD is rotating at a constant angular speed of 200 revolutions per minute, then the tangential velocity of a point on the circumference is:

Answer 1

Hi there!

Converting from angular velocity to tangential velocity can be done by:

v = ωr

v = tangential velocity (m/s)

ω = angular velocity (rad/sec)

r = radius (m)

Convert 12 cm to meters:

100 cm = 1 m

12 cm = 0.12 m

Now, convert rev/min to rad/sec:

${\frac{200rev}{min}} * \frac{1min}{60s} * \frac{2\pi rad}{1 rev} = 20.94 rad/sec$

v = 20.94 · 0.12 = 2.51 m/s