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Force and Motion

  1. Oct 20, 2009 #1
    A 53 kg skier skis directly down a frictionless slope angled at 15° to the horizontal. Choose the positive direction of the x axis to be downhill along the slope. A wind force with component Fx acts on the skier. What is Fx if the magnitude of the skier's velocity is (a) constant, (b) increasing at a rate of 1.5 m/s2, and (c) increasing at a rate of 3.0 m/s.
  2. jcsd
  3. Oct 20, 2009 #2
    give us the atempt at the sulution then we can try to help u
  4. Oct 20, 2009 #3
    i did it and got
    a: 137.17 n
    b: 57.5 n
    c: -22n

    but im pretty sure they're wrong:P
  5. Oct 20, 2009 #4
    with wich formula

    did u do this with the one of potencial energy
  6. Oct 20, 2009 #5
    sigma Fext= M.a newton's second law i think:P .. and u place the forces.. that's how i did it.
  7. Oct 20, 2009 #6
    so u did this with the second law of newton f=m x a
  8. Oct 20, 2009 #7
    yes|-) .. now can someone help me please^o)?
  9. Oct 20, 2009 #8
    There are two forces, the force of the wind and his weight (only in the c-direction, down the ramp).

    a) Constant velocity means that there is no acceleration and the net force is zero.

    b/c) He is accelerating down the hill which means that there is a net force.

    Draw an fbd then you can create an equation for a/b/c based on the parameters.
  10. Oct 20, 2009 #9
    u did just the forces but how about the angel thats ur failur a
  11. Oct 20, 2009 #10
    nah he did that with the f=ma parameters but u need to put the angel so if it is like u say it will go like this f=ma=53kg x o m/s2 and then he would have o N and u would do 2 and 3 like this
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