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Homework Help: Acceleration Problem

  1. Jan 12, 2004 #1
    Hi guys,

    I have a homework problem which I can use some help with:

    Lisa harnesses two pets to a wagon. The mass of the wagon is 12 kg, and it rolls without friction on a horizontal floor. Pet 1 is pulling at 15 degrees left of forward with the force of 5 N. Pet 2 is pulling at 30 degrees right of forward. How much force does Pet 2 exert if the wagon acclerates straight forward?

    I also attached a picture

    thanks in advance,


    Attached Files:

  2. jcsd
  3. Jan 12, 2004 #2
    Well, I'm kind of lazy to do actual math for you, but I will give you hints on doing it.

    First off, when you got two pets moving in different directions like that, you will definitally want to find the tension in the ropes to the wagon. By finding the tension caused by the pulling, you should be able to find the combined force on the wagon.
  4. Jan 12, 2004 #3
    I think I got it, does 2.588N sound about right?
  5. Jan 12, 2004 #4
    I don't know where this attached picture is, but...

    Code (Text):

    \<--^  ^-->/
     \15|  |30/
      \ |  | /
    F=5\|_ |/F=x
       | \\ |
       | \\ |
       | \\ | <--- Wagon
    So basically this is how it has to work. Since the wagon is going to accelerate straight forward, you want the X-Components of each force which pet 1 and pet 2 exert to be equal and opposite, and hence no acceleration in either the left or right direction.

    the X-Component for pet 1 will be 5*sin 15. The X-Component for pet 2 must be equal so:

    5*sin 15 = x sin 30

    solving for x:

    x := (5*sin 15)/(sin 30)

    this will give you the force which pet 2 exerts on the wagon

    Or at least this is how I interpreted the question.

    edit:Ok, you posted heheh. Yes, that is the same answer as I got, so I'm assuming you did it correctly :)
    Last edited: Jan 12, 2004
  6. Jan 12, 2004 #5
    I used almost the same thing, but did the cos of the supplements but same idea, thanks for your reply :smile:
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