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Homework Help: I need help with a problems

  1. Sep 14, 2005 #1
    Well I've been working on these last two problems and I just can't figure them out. Can someone just point me in the correct direction?

    1.) A golf ball is struck with a five iron on level ground. It lands 105.0m away 3.80 s later. What is the magnitude and the direction of the initial velocity?(Neglect air resistance.)

    This is what I have for this problem: V=105/3.8 = 27.63m/s
    Then I used y = Vyot - (1/2)g t^2 the answer from this was 70.76 for which I then used 70.76 sin 27.63 to get an angle.

    thanks in advance for the help

    kwesi
     
  2. jcsd
  3. Sep 14, 2005 #2

    Fermat

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    Homework Helper

    Check your working again for the velocity of 70.67.
     
  4. Sep 14, 2005 #3
    Careful there, that's just the (constant) speed in the horizontal direction. If you want to use the formula [tex]y(t) = V_{y}(0)\cdot t - \frac{1}{2}gt^{2}[/tex], try to fill in the values for the moment the ball touches down again. You should end up with [tex]V_{y}(0)[/tex]. Then you'll have both components of the initial velocity vector, and from there it's just a small step to complete the answer.
     
  5. Sep 14, 2005 #4
    thanks for the info I was able to figure it out with your help.
     
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