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Homework Help: Easy force/impulse question

  1. May 19, 2010 #1
    We are doing this for our physics class, and they are very basic, easy questions. But it is worth a lot, and might end up being our final. (We're allowed to get help any way possible)

    1. The problem statement, all variables and given/known data
    A cannonball shot from a long-barrel cannon travels faster than one shot from a short-barrel cannon because the cannonball receives greater
    a. force
    b. impulse
    c. both a and b
    d. neither a and b

    2. Relevant equations

    impulse= Ft


    3. The attempt at a solution

    I think it is just b, instead of c, because I don't think there is a greater force. It doesn't indicate that a greater force is used on the bigger cannon. But the longer barrel gives it more time, therefore a greater impulse, right?

    Just having a brain fart. :P And the easier problems get me, because I over-analyze.
  2. jcsd
  3. May 19, 2010 #2


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    Yes, you are correct. But I wouldn't say the problem was easy. It requires some conceptual thought, which you have explained well. Essentially, the longer barrel provides more time for the ball to reach greater speed (greater momentum change from the greater impulse) before it leaves the barrel.
  4. May 19, 2010 #3


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    Given the way the problem is stated (or at least the way I'm interpreting it), I would have to agree with your answer. :approve:

    [Edit: PhanthomJay beat me to the punch. I guess it serves me right for procrastinating my replies.]:smile:
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