A uniform 2.00-kg circular disk of radius 20.0 cm is rotating ...

[james9437]

A uniform 2.00-kg circular disk of radius 20.0 cm is rotating clockwise about an axis through its center with an angular speed 30.0 revolutions per second.
 
  A second uniform 1.50-kg circular disk of radius 15.0 cm that is not rotating is dropped onto the first disk so that the axis of rotation of the first disk passes through the center of the second disk. What is the final angular speed of the two disks when they are rotating together?
  A)
 
  16.9 revolutions per second
  B)
 
  19.2 revolutions per second
  C)
 
  21.1 revolutions per second
  D)
 
  17.1 revolutions per second
  E)
 
  12.7 revolutions per second

Question 2

State Kirchhoff's junction rule.
 
  What will be an ideal response?

[janieazgirl]

Answer to Question 1

C

Answer to Question 2

At any junction point, the sum of all the currents entering the junction must equal the sum of all the currents leaving the junction.

[james9437]

Thanks for the timely response, appreciate it

[abro1885]

Wow, this really help