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Homework Help: Two objects meet

  1. Nov 16, 2009 #1
    tow students are randomly attacking each other with water balloons. one student is on the roof and the other is on the ground below.

    the student on the roof throws a water balloon straight down with an initial speed of 5.2m/s and the student below throws his up at a rate of 7.1m/s. if the height of the building is 10m,

    determine where and when the two balloons meet??

    [i dont knooow!!!]
  2. jcsd
  3. Nov 16, 2009 #2
    Ok so this is kind of like projectile motion only in one dimension. When working with problems like this it is important to draw a diagram. It also makes it easier if you solve for one balloon at a time.
  4. Nov 16, 2009 #3
    i drew the diagram...but i dont know how to start to solve, if you help me to get started i can do the rest
  5. Nov 16, 2009 #4
    Well how do you think you would start it? You don't have to use equations or anything. Try to tell me in words what you would have to do.
  6. Nov 16, 2009 #5
    ok so.
  7. Nov 16, 2009 #6
    i started to solve the problem by naming the unknows and what data is given. and i called the boy on the roof B1 and the other boy B2

    i also have acceleration= 9.8 m/s2
  8. Nov 16, 2009 #7


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    Homework Helper

    ok so....

    - deal with each balloon individually first
    - write down the forces and initial velocity at time t=0 on each baloon
    - use these to find the velocity & positon at time t of each baloon

    from there you'll need to equate the positions and solve for the time t when they collide
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