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Homework Help: Dynamics systems question

  1. Oct 13, 2012 #1
    Hey! I'm having some problems with this question:
    An electric winch is used to raise a 40-kg package and a 10-kg package vertically up the side of a building as pictured in the diagram. The magnitude of the frictional force acting between the wall and the 40-kg package is 60N. The angle the cable makes to the vertical is 15. If the packages are lowered with an acceleration 1.0 m/s2 [D], what is the tension in the cable between the winch and the 40.0 kg package?

    We were also given a diagram:

    How i solved it:
    (1) Fnet y= Fg1+Fg2+T2+T1Y+FK
    mnet(anet)= Fg1+Fg2-T2-T1Y-FK
    (2) Fnet=Fg+T2
    T2 = 88N
    (3) mnet(anet)= Fg1+Fg2-T2-T1Y-FK
    (50)(0.1)= 40(9.8) + 10(9.8) -88 -T1Y- 60
    T1Y= 292N
    (4) Sin?=o/h
    h = 302.3 N

    Is how i solved it right? If not is there another way I should be solving it?
    Last edited: Oct 14, 2012
  2. jcsd
  3. Oct 13, 2012 #2
    Draw a force diagram for each block separately. (1) and (3) are wrong. You also didn't use the right numbers when you plugged in to (2).
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