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: Three dimensional collision with bowling ball and pin.

  1. Oct 25, 2011 #1
    1. The problem statement, all variables and given/known data
    In order to convert a tough split in bowling, it is necessary to strike the pin a glancing blow as shown in the figure. Assume that the bowling ball, initially traveling at 15.0 m/s, has eight times the mass of a pin and that the pin goes off at 75° from the original direction of the ball.

    9-49.gif

    (a) Calculate the speed of the pin.
    (b) Calculate the speed of the ball just after collision.
    (c) Calculate the angle θ through which the ball was deflected. Assume the collision is elastic and ignore any spin of the ball.

    2. Relevant equations
    MbVb+MpVp=MbVB+MpVP (Mb=mass of ball, Mp=mass of pin, Vp=initial velocity for pin, VP=final velocity for pin, Vb=initial velocity for ball, VB=final velocity for ball.)


    3. The attempt at a solution
    I have no idea how to even attempt this problem.
    1. The problem statement, all variables and given/known data



    2. Relevant equations



    3. The attempt at a solution
     
  2. jcsd
  3. Oct 25, 2011 #2
    Try writing down your Conservation of Momentum equations
     
  4. Oct 25, 2011 #3
    Should I write down the formula first? Should I plug in the numbers and continue trying to cancel out unknown variables? The conservation of energy and momentum equations are realllllly long -_-
     
  5. Oct 27, 2013 #4
    I would like too bump this-I have the same question!
    I tried so far using the p=mv equation in both dimensions (since in the x direction it equals zero!), however I can't seem to solve for what they're asking…my algebraic manipulations aren't as well.
     
  6. Oct 28, 2013 #5

    CWatters

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    This is in the homework section and the forum requires you to show your working/attempt. How else can we see where you are going wrong ;-)

    It's not usually a good ide to plug in the numbers early on.
     
  7. Oct 28, 2013 #6

    bobie

    User Avatar
    Gold Member

    Hi, I do not know if the formula for balls is valid for pins, if it is ...then
    you know cos λp (75°) = 0.2588 and the ratio Rm of Mb to total mass 8/9
    you get quickly vp = v0* cos λ* 2R (15*0.25*16/9) = 6.9 m/s
    the you can easily find all missing data (with the E and p formulas.)
     
  8. Oct 28, 2013 #7

    CWatters

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    The problem statement contains no information on the vertical dimension so this is really a 2D problem.
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted