1. Not finding help here? Sign up for a free 30min 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!

Angular impulse

  1. Apr 16, 2014 #1
    1. The problem statement, all variables and given/known data
    A thin rod of length L, mass m is suspended horizontally at rest. It is suddenly released and experiences immediately after an impulse vertically upwards at one end.

    I need to find the maximum height reached by the centre of mass and the angular velocity of rotation about the centre of mass.

    3. The attempt at a solution
    I can't see how there is enough information given in the question. I have used the fact that J=0.5Lp here (J is angular momentum) from the relation between angular and linear impulse, and then this means 0.5Lmv=Iω, with I=mL2/12. Then 0.5Lmv=mL2ω/12. This relates v and ω by v=ωL/6. I could then probably work with constant acceleration formulae to get the answer, however both v and ω are unknowns (and I have to find ω in the next part) so I have no idea where to go.

    Thanks in advance :)
     
  2. jcsd
  3. Apr 16, 2014 #2
    The initial velocity of CM ,angular velocity of the rod and the maximum height reached all depend upon the magnitude of impulse . So surely some data is missing from the question.
     
  4. Apr 16, 2014 #3
    Yes, as I suspected. Thanks for clarifying.
     
  5. Apr 16, 2014 #4

    BiGyElLoWhAt

    User Avatar
    Gold Member

    Well to me it looks as thought OP isn't supposed to solve for a number, but max height as a function of I.
     
  6. Apr 16, 2014 #5

    BiGyElLoWhAt

    User Avatar
    Gold Member

    Length L, mass M, impulse, I...
     
  7. Apr 16, 2014 #6

    haruspex

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member
    2016 Award

    Except that no label is given for the impulse in the question as stated in the OP - that's what's missing.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted



Similar Discussions: Angular impulse
  1. Angular Impulse (Replies: 0)

Loading...