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Homework Help: Force- Physics?

  1. Nov 13, 2008 #1
    http://physicsed.buffalostate.edu/c...anics/PDF files/4-FP-Inertia/Tests/Quiz 1.pdf

    1) I don't know how to do this, but I know there is the force of gravity by the earth in the force diagram..

    2) For this one I got the answer
    Fx=7.5N [I did 1/2(15N) which equals 7.5 N]
    Fy=13N [I took my x component 7.5N and I did 7.5sqrt3=13N]
    Did I solve this problem right??

    3) How do you write an equation for this diagram?

    Can you tell me if I did the Bonus right?

    T1cos(60)=T2
    T2sin(60)= 3kg

    T1sin(60)=3kg
    I divided both sides by sin(60) to make T1 by itself so
    T1sin(60)/sin(60)=3.464
    SO T1=3.464

    I took T1=3.464 and plug it into T1cos(60)=T2
    3.464cos(60)=T2
    T2=1.232

    So I don't know if I got that one right??
    My answer is T1=3.464 and T2=1.232

    Please help me..I really need this. Thank you!
     
  2. jcsd
  3. Nov 13, 2008 #2
    1) There is also a normal force and a kinetic frictional force.
    2) You need to resolve your vector into components using trig.
    3) The system seems to be in equilibrium, so

    [tex]F_{xnet}=0[/tex]

    and

    [tex]F_{ynet}=0[/tex]

    Start from there and re-think your strategy for the bonus part. For one, tension is a force so you can't measure it in kg...Remember Newton's second law.
     
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