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Pumpkin in Cannon Acceleration Problem

  1. Oct 13, 2011 #1
    1. The problem statement, all variables and given/known data
    Someone wants to build a Jack-o-lantern launching cannon. He wants to launch a 5kg pumpkin a distance of 50m, but he also knows that an acceleration of more than 5 g's will crush the pumpkin in the cannon. What length does the barrel of the cannon need to be, and how much average force should the cannon exert on the pumpkin? You may assume that both force and acceleration remain constant within the barrel, and that no matter what angle you chose, the pumpkin will land at the same height as the end of the barrel?

    I am using 45 degrees as the angle, sorry I forgot about that.

    2. Relevant equations Not exactly sure?

    3. The attempt at a solution I was able to solve for the initial velocity of the pumpkin, getting 22.14 m/s. But I don't know where to go from here or if it is even useful?
    Last edited: Oct 13, 2011
  2. jcsd
  3. Oct 13, 2011 #2
    if you have the initial velocity necessary to launch it 50 metres then you will just have to find out how long the barrel needs to be to get it to that speed at a constant acceleration of 5g.
  4. Oct 13, 2011 #3
    there is also a missing parameter in your equation. There is no angle of the barrel, and there is no height of the cannon. You might be able to assume that the cannon starts right on the ground, but the angle needs to be given. With that being said, how did you calculate 22.14m/s?
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