Suppose a piece of dust finds itself on a CD.

Question

Suppose a piece of dust finds itself on a CD. If the spin rate of the CD is 455 rpm, and the piece of dust is 4.4 cm from the center, what is the total distance traveled by the dust in 4 minutes? (Ignore accelerations due to getting the CD rotating.)

Answer 1

Michelle,

The key here is realizing that the distance in one revolution is the circumference of the circle of radius 4.4cm.  C = 2πr So it turns into a series of multiplications.  Watch the units.

2π(4.4) cm./rev. * 355 rev./min * 4 min = 

You can take it from here. 

Mary