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Homework Help: Explosion of ball

  1. Oct 14, 2011 #1
    Explosion of ball!!

    1. The problem statement, all variables and given/known data

    An object with total mass mtotal = 16.6 kg is sitting at rest when it explodes into three pieces. One piece with mass m1 = 4.9 kg moves up and to the left at an angle of θ1 = 18° above the –x axis with a speed of v1 = 25.5 m/s. A second piece with mass m2 = 5.5 kg moves down and to the right an angle of θ2 = 23° to the right of the -y axis at a speed of v2 = 23.9 m/s.

    What is the x-component of the velocity of the third piece

    2. Relevant equations
    I know the final P=0 and the mass of the third object = 6.2kg



    3. The attempt at a solution
    I tried finding the x component for m2 which I got to be 10.144 by tan(23)*23.9, and we know the x component of m1, so I multiplied these x components by their masses and added them, since P=0 I then subtracted them to the other side of the = sign to give me the opposite. I dont know if I am on the right track or not. I have tried every way I can think of to do this problem, cant get the right answer.
     
  2. jcsd
  3. Oct 14, 2011 #2

    ehild

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    Homework Helper

    Re: Explosion of ball!!

    You are on the right track that the sum of the momentums is zero. Show your calculations in detail. I can not follow you from that you have. How do you get the x component of a vector?

    ehild
     
  4. Oct 14, 2011 #3
    Re: Explosion of ball!!

    I was doing it wrong, and then I thought I was doing it correctly now, but am still getting the wrong answer. I am finding the x and y of each piece that we are given theta by taking the cos(theta)=x/v then found x(cm) by taking the x value and multiplying it mass then dividing by total mass, once I got both x's for both thetas given I found the difference between the two , I did this because I know P=0 so I want them to sum to 0, since I have one piece that goes in the negative x direction I made that negative and still cant figure out what I am doing wrong.
     
  5. Oct 14, 2011 #4

    ehild

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    Re: Explosion of ball!!

    Write out the calculation with formulas. What are the x components of the momentum of both pieces?

    ehild
     

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    Last edited: Oct 14, 2011
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