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Homework Help: Er please help me

  1. May 7, 2009 #1
    1. The problem statement, all variables and given/known data

    In a new twist on the birthday party game, a piñata hangs from the branch of a very tall tree. Nathan aims and fires a small rock from the ground at an angle θ above the horizontal. He fires it at velocity vo. The rock strikes the piñata just as it reaches the top of it trajectory.

    a. Ignoring air resistance, what is the speed with which the rock hits the piñata?
    b. Calculate the speed of the rock when it hits the piñata assuming an initial speed of 9.0ms-1 and an angle of 65º with respect to the ground.
    c. How high is the piñata?
    d. How long will it take the lollies inside the piñata to hit the ground once the piñata breaks?

    2. Relevant equations

    er i honestly have no idea how to approach this question i know that u use one of the equations of motion i am assuming


    it the angle thing thats has got me can someone please push me in the right direction???

    3. The attempt at a solution
  2. jcsd
  3. May 7, 2009 #2
    Have you heard of 'resultant speed' ?

    You can split a speed in that direction into a 'horizontal speed' & 'vertical speed', using pythagoras, see where you get from there. (Try drawing a right angled triangle)

    (Hint: to work out how high the rock will go you're only interested in the vertical)

    Edit: And question D? LOL
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