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
A) 1.06 m/s.
B) 1.26 m/s.
C) 1.39 m/s.
D) 1.62 m/s.
E) 1.32 m/s.

Question

Quizplus · Accepted Answer

We can use the formula for tangential velocity:

v = rω

where v is the tangential velocity, r is the radius of the circle (which is half the diameter), and ω is the angular speed.

The radius r is 12.0 cm / 2 = 6.0 cm = 0.06 m.

We need to convert the angular speed from revolutions per minute to radians per second:

ω = (200 rev/min) × (2π rad/rev) × (1 min/60 s) = 20.94 rad/s

Now we can plug in the values:

v = (0.06 m) × (20.94 rad/s) = 1.26 m/s

Therefore, the tangential velocity of a point on the circumference is 1.26 m/s, which corresponds to choice B.

A CD Has a Diameter of 12