SOLUTION: Consider a spinning CD which has a mass of 15.0 g. If the radius of the CD is 8.3 cm, and if it rotates about its centre at an angular frequency of 44.4 rad/s, what is its rotation

Algebra ->  Finance -> SOLUTION: Consider a spinning CD which has a mass of 15.0 g. If the radius of the CD is 8.3 cm, and if it rotates about its centre at an angular frequency of 44.4 rad/s, what is its rotation      Log On


   

Question 1128404: Consider a spinning CD which has a mass of 15.0 g. If the radius of the CD is 8.3 cm, and if it rotates about its centre at an angular frequency of 44.4 rad/s, what is its rotational kinetic energy (in J)? Assume the CD is a solid disk (i.e. ignore the hole in the center.).
Answer by ikleyn(52776) About Me  (Show Source):
You can put this solution on YOUR website!
.

For a disk of mass  M  and radius  R,  the moment of inertia  I  is

    I = 1%2F2.M%2AR%5E2.


If the disk is spinning with angular speed  alpha radians per second, its rotational kinetic energy is
    
    K.E. = %281%2F2%29%2AI%2Aalpha%5E2 = %281%2F2%29%2A%281%2F2%29%2AM%2AR%5E2%2Aalpha%5E2 = 1%2F4.M%2AR%5E2%2Aalpha%5E2.


What you need to do now is to substitute your data; to take your calculator and to complete calculations on your own.

Be sure to have the mass in kilograms and the radius in meters.


The reference is this link.

https://www.unr.edu/Documents/science/physics/labs/180/11_Rotational_Kinetic_Energy.pdf