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!

Homework Help: Laser experiment, determine angular velocity

  1. Aug 16, 2013 #1
    1. The problem statement, all variables and given/known data

    A circular cannister of some reflective liquid is spinning at some ω. The distance between the cannister and the surface is given by

    h(r) = h(0) + (ω2/2g)r2

    Where g ≈ 9.82 and r is the distance to the axis of revolution. When we shine two parallell laser beams on the surface, we find that they meet at a point 22 cm above the surface.

    Find ω.

    2. Relevant equations

    f = R/2

    3. The attempt at a solution

    We have a parabolic mirror with radius of curvature = 0.44 m. But I'm not really sure how to find the equation for a parabola given the curvature. I was well on my way to taking the gradient of the parabola and setting up some kind of system of vector equations, but I suspect that would be overkill...
     
  2. jcsd
  3. Aug 16, 2013 #2
    Figured it out.
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted



Loading...