a) circumference = 2 pi r = 2pi(6)= 37.7 cm = 0.377 m b) speed = 4 x circumference = 0.377 x 4 = 1.51 m/s c) angular speed is proportional to distance from the center. if radious is halved, the speed is halved. therefore speed at 3 cm = 1.51 /2 = 0.75 m/s
A compact disc has a radius of 6 centimeters. a. What is its circumference in meters? b. If the cd rotates 4 times per second, what is the linear speed of a point on the outer edge of the cd? Give your answer in meters per second. c. What is the linear speed of a point 3 centimeters from the center of the cd? (Assume the angular speed has not changed).