A blu-ray drive has a maximum speed of 10,000 revolutions per minute. if a blu-ray disc

a blu-ray drive has a maximum speed of 10,000 revolutions per minute. if a blu-ray disc has a diameter of 12 cm, what is the linear speed, in km/h, of a point 4 cm from the center if the disc is spinning at a rate of 8000 revolutions per minute?