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!

Impulse and Momentum: Gernade Problem

  1. Apr 5, 2009 #1
    1. The problem statement, all variables and given/known data
    A grenade of mass 10kg explodes into three pieces in the same plane, two of which, A(5.0kg) and B(2.0kg), move off as shown. Calculate the velocity of the 3.0 kg third Piece, C
    scan0001.jpg

    2. Relevant equations
    Pt=Pt'


    3. The attempt at a solution
    scan0002.jpg

    I do not get the right answer at all. I'm not sure where i'm going wrong.
     
  2. jcsd
  3. Apr 5, 2009 #2

    LowlyPion

    User Avatar
    Homework Helper

    Figure momentum is going to be conserved.

    Isn't it really a matter of vector addition?

    Pa = Ma*(-Va*cos30 i + Va*sin30 j)
    Pb = Mb*(...

    These added together give you -Pc don't they?
     
  4. Apr 5, 2009 #3
    I'm not really sure what you mean. The way I did is the way my Teacher told me to. I'm my class is tough through Video Conference so its hard to ask her. I told her I wasent getting the right answer and she said to do it exactly the way i have it. Her answer is 128.93 m/s [R82°D]
     
  5. Apr 5, 2009 #4

    LowlyPion

    User Avatar
    Homework Helper

    I was merely treating momentum as vectors and taking the components independently.

    As an alternative method, consider the momentum in x and the momentum in y, separately.

    Pax + Pbx + Pcx = 0

    and

    Pay + Pby + Pcy = 0

    Once you have determined the components of Pc then you can use Pythagoras to give you Pc.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Impulse and Momentum: Gernade Problem
Loading...