1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Increasing speed by decreasing intertia?

  1. Nov 21, 2015 #1
    Just curious, explanation if youre going to answer please!!

    2 horizontal disks stacked on one another spinning at constant v, (about a frictionless axis perpendicular to their center), both have mass.

    Okay, so lets say its possible to instantaneously remove the top disk. So would that make the other spin faster?
     
  2. jcsd
  3. Nov 21, 2015 #2

    Drakkith

    User Avatar

    Staff: Mentor

    It would not. Each disk has its own velocity, momentum, inertia, etc. Removing one does not change the other. We don't even need to magically remove one of the disks. We can just assume there is some mechanism that pushes the top disk off of the bottom disk and off of the axle connecting the two.
     
  4. Nov 22, 2015 #3

    CWatters

    User Avatar
    Science Advisor
    Homework Helper

    +1.

    It would be possible for the top disc to slow down and the bottom one to speed up if the mechanism that separates them was correctly designed.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook