A DVD is 12 centimeters in diameter The drive motor of the D

A DVD is 12 centimeters in diameter. The drive motor of the DVD player is controlled to rotate at 3.5 revolutions per second. Find the linear speed of a point that is 4 cm from the center of the disk. (Round answer to nearest integer).

Solution

perimetre = pi* 12 = 12pi

linear speed that is 4 cm from the center

perimeter = 2pi * 4 = 8pi

hence, linear speed = 3.5* 8pi

= 88 cm / sec