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Homework Help: 2d motion

  1. Sep 29, 2010 #1
    1. A fishing line is cast at 27 m/s at an angle of 33 degrees above the horizontal from the top of a 15m tall bridge. Find the time until the line hits the water below and find its velocity when it hits.



    2. Relevant equations
    x=xo+vot+1/2at2
    v=vo+at



    3. The attempt at a solution
    I first found my component velocities and then the time by using the x=.... equation above. I broke it up into 2 parts: the time it took to leave the bridge to the time it was level with the bridge on its downfall and i got 2.94s. Then i found the time it took to go from the point level with the bridge to the water and got .8s. I then added 2.94+.8=3.74s*.
    To find the velocity i plugged my numbers in to v=... equation above and got 22.69m/s*.

    Someone please check and see if I did this correctly! I'm not sure if I was supposed to break it into 2 parts to find the time!
    1. The problem statement, all variables and given/known data



    2. Relevant equations



    3. The attempt at a solution
     
  2. jcsd
  3. Sep 29, 2010 #2
    A tip, when you preview the first post it puts the template in again, it helps to edit that out.

    As for breaking it into two parts...my high school teacher described it as the tricycle method. There's a simpler way to do this.

    However, why does your X component have acceleration in it? Remember projectiles are only affected by the force of gravity.
     
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