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New to forum and having major problems with couple problems

  1. Jan 29, 2009 #1
    New to forum and having major problems with couple problems!!

    1)Two cars are towing a housing unit to a new location. The sum of the forces vector F A and vector F B exerted on the unit by the horizontal cables is parallel to the line L, and FA = 3200 N. Fa(angle)=48, Fb(angle)=32
    Determine FB N.?
    -using vectors but cant seem to find Fb N.....

    3)The two masses shown in the figure are each initially 1.80 m above the ground, and the massless frictionless pulley is fixed 4.8 m above the ground. (mA = 1.5 kg and mB = 3.3 kg.) What maximum height does the lighter object reach after the system is released? [Hint: First determine the acceleration of the lighter mass and then its velocity at the moment the heavier one hits the ground. This is its "launch" speed. Assume the mass doesn't hit the pulley. Ignore the mass of the cord.]


    5)Francesca dangles her watch from a thin piece of string while the jetliner she is in accelerates for takeoff, which takes about 14 seconds. Estimate the takeoff speed of the aircraft if the string makes an angle of θ = 35° with respect to the vertical.


    9)A jet aircraft is accelerating at 4.7 m/s2 as it climbs at an angle of θ = 45° above the horizontal (see figure). What is the total force that the cockpit seat exerts on the 85 kg pilot?


    10)A child slides down a slide with a 25° incline, and at the bottom her speed is precisely half what it would have been if the slide had been frictionless. Calculate the coefficient of kinetic friction between the slide and the child.


    17)A child slides down a slide with a 25° incline, and at the bottom her speed is precisely half what it would have been if the slide had been frictionless. Calculate the coefficient of kinetic friction between the slide and the child.
    -

    Any kind of help would be helpful, cause im just stumped right now....

    thanks in advance
    ssman
     
  2. jcsd
  3. Jan 29, 2009 #2

    Delphi51

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    Homework Helper

    Re: New to forum and having major problems with couple problems!!

    You are supposed to show us your attempt so we can constructively criticize and not just do your homework for you! You should have a diagram with two forces and two triangles which you may not be able to show here, but you can show your trigonometry.
     
  4. Jan 29, 2009 #3
    Re: New to forum and having major problems with couple problems!!

    ...im not asking for the answers, just how to start the problem or formulas to use because i dont know where to start. the other problems weren't as bad but just these six are giving me a lot of problems. sorry im not trying to get the answers just to be pointed in the right direction.

    thanks
     
  5. Jan 29, 2009 #4
    Re: New to forum and having major problems with couple problems!!

    3)?

    5) tan(35)g=a? but its saying im wrong....

    9) ?

    10) ?

    17) On an ice rink two skaters of equal mass grab hands and spin in a mutual circle once every four seconds. If we assume their arms are each 0.75 m long and their individual masses are 65.0 kg, how hard are they pulling on one another?

    T=2(pi)r/v
    T=(2(pi).75(2))/4 = 2.4

    a=(v^2)/r
    a=3.84

    F= 65x2(3.84)=499.2N
     
  6. Jan 29, 2009 #5

    Delphi51

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    Homework Helper

    Re: New to forum and having major problems with couple problems!!

    Sketch your FA - 3200 N at an angle of 48 degrees up from horizontal. You must find the horizontal component of that, so draw an arrow to the right and then at the end of it, an arrow up so it ends at the end of FA. You are showing FA as the sum of a horizontal vector and a vertical vector. Using sine and cosine you can find the length of these vectors. Do the same for Fb.
     
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