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Homework Help: Magnitude and direction of the resultant force

  1. Jan 7, 2006 #1
    1. Three ropes are tied to a box and three boys exert the following forces:
    F1=220 N @ 90 degrees
    F2=185 N @ 165 degrees
    F3=235 N @280 degrees

    Determine the magnitude and direction of the resultant force.

    For my solution I made a Vector Componant table, found the total force on the x and y axis. Transferred that to a diagram and found the resultant force to be 142.6 N in a direction of 165.2 degrees.

    2. You head across the Battle River in your boat with a velocity of 8.0 m/s, south. The river is flowing at 2.8 m/s, east.

    a) Determine the magnitude and the direction of the resultant velcity vector.
    b)Assume that you and you boat have a total mass of 192 kg. Calculate the direction of the momentum of you and your boat as you cross the river.

    This question seemed to be really simple. I got the resultant velocity to be 8.5 m/s in a direction of 289.3 degrees. For the next part I found the momentum to be 1623 kgm/s, and wouldn't the direction be the same as the velocity?
  2. jcsd
  3. Jan 7, 2006 #2
    Yeah, I didn't check it but it looks as though everything is correct. For the boat you should include the direction (i.e. 19.3 degrees east of south or whatever the angle was relative to).
    Last edited: Jan 7, 2006
  4. Jan 7, 2006 #3
    Alright Thanks, and a little heads up for everyone here. I'll be one these forums alot, because I'm taking Physics by correspondance.
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