What should be the angular velocity of disk B so that the linear velocity of both the disks remains same.

Two circular disks A and B of the same mass but are with different radii r_A=10cm and r_B=20cm respectively. Disk A rotates with an angular velocity of 60 rad/s. What should be the angular velocity of disk B so that the linear velocity of both the disks remains same.

a. 25 rad/s
b. 20 rad/s
c. 30 rad/s
d. Data insufficient

Correct Answer : c. 30 rad/s

Explanation :

Using the formula v = rω where v is the linear velocity, r is the radius of disk and ω is the angular velocity.