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: Rod is toppling. Find reaction force as a function of theta

  1. Dec 20, 2016 #1
    1. The problem statement, all variables and given/known data
    Rod of length b and mass m topples from vertical position at theta = 0. Calculate the reaction force f as a function of theta. What is the minimal and maximal values of f for theta between 0 and pi

    2. Relevant equations
    Third law?

    3. The attempt at a solution
    I never really worked a problem such a this in mechanics. So I was shocked to see this on my exam. I would like to know what the solution is. I had no idea how to solve. I suppose this falls under rigid body motion, but all we worked in that topic were lagrangians.....
  2. jcsd
  3. Dec 20, 2016 #2
    can the rod slip on the ground?
  4. Dec 20, 2016 #3


    User Avatar
    Science Advisor
    Homework Helper
    2017 Award

    In general, exam questions are related to the material that's been presented. So you wrote a Lagrangian for this constrained system and found the equation of motion. Did you also learn that the constraint forces follow from the Lagrangian multipliers ?
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted