You have invented a new recording device that uses a disk of radius 4.1 mm, simi

Question

You have invented a new recording device that uses a disk of radius 4.1 mm, similar to a DVD or CD (see figure). The outermost track is with radius 4 mm and the innermost track is with radius 1 mm. The reading speed (linear speed) is kept constant irrespective of the position on the disk by adjusting the angular velocity depending on which track is being read. The angular velocity of the disk when the outermost track is being read is 241 rad/s.

- After a recording is over, the disk must be stopped. The reading ends at the outermost track. What is the magnitude ? of the uniform angular acceleration required to stop the disk rotating at 241 rad/s after 12 full rotations? Can you please explain the steps leading to the solution? Thanks!!!

Explanation / Answer

Using 3rd equation of angular motion,

w^2 = wo^2 + 2 a theta

Given, wo = 241 rad/sec

Theta = 12 x 2 pi = 75.40

So, a = - 241^2/ (2 x 75.40)

Angular acceleration, a = 385.2 rad/s^2 (Ans)

Comment in case any doubt, please rate my answer ...

Related Questions

Navigate

• Browse (All)
• Browse Y
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.