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Homework Help: Physics (Net Forces/Newton's laws)

  1. Nov 16, 2008 #1
    Alright well I have 2 questions im stuck on.

    first is:

    Four forces act on a hot-air balloon, shown from the side in the figure below. Find the magnitude and direction of the resultant force on the balloon if F1 = 4600 N, F2 = 1250 N, F3 = 1000 N, and F4 = 4200 N.

    F1 is pointing up, F4 is pointing down, F2 is pointing left and F3 is pointing right.

    It asks for the force in N and at what degree clockwise from F2.

    I got the force to be 300 N northward, and 250 N to the lef (west). I dont get how to get the Degree(direction) clockwise from F2. Any help?

    And the other problem is:
    An 1750 kg car is moving to the right at a constant speed of 1.92 m/s.

    (a) What is the net force on the car?
    _______ N to the right
    (b) What would be the net force on the car if it were moving to the left?
    _______ N to the left

    I dont really know what to do here. i just used F=MA but it was wrong. i dont think 1.92 m/s can be used since it isnt acceleration but i dont really know what to do. any help?
    1. The problem statement, all variables and given/known data

    2. Relevant equations

    3. The attempt at a solution
  2. jcsd
  3. Nov 17, 2008 #2


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    Science Advisor
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    Gold Member

    You have the components of the resultant, can you find the magnitude of the resultant using the Pythagorean Theorem? Can you find the angle of the resultant using the trig properties of a right triangle?
    You must use the acceleration. What is the car's acceleration if it is moving at constant speed?
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