Recent content by kffd

  1. K

    Ladder leaned against a wall; forces

    = 0.5 mg cotθ I think that's all. Thanks a lot, ehild and haruspex; I've been out of school sick recently, going through this problem with me really did help me catch up. Once I'm a bit more learned when it comes to physics, I'll do my diligence to help out some other people on here, too. :)
  2. K

    Ladder leaned against a wall; forces

    Well, net torque must be 0 if it's in equilibrium. So, mg 2.5cosθ - 5sinθ Ff = 0 I used a minus just to indicate that one direction is negative. (I arbitrarily picked clockwise.) Going off of that: mg 2.5cosθ = 5sinθ Ff Ff = (mg 2.5cosθ)/(5sinθ) Ff = FNwall, so FNwall = (mg 2.5cosθ)/(5sinθ)...
  3. K

    Ladder leaned against a wall; forces

    Ok, good news is I knew that about torque, at least. That's what I didn't understand, how a "torque" could work if it were simply a line. (We have only discussed it as clockwise/counterclockwise.) |\-LOA-> |..\...| |...\...| |...\.| |...θ\ I think that is the line of action, and the vertical...
  4. K

    Ladder leaned against a wall; forces

    Another go for FNwall: 5sin θ x Ff Here's a diagram to help explain what I'm not getting: ||\ ||..\ ||...\--> ||...\ v|...θ\ Vertical arrow is what I now think torque for FNwall should be, 5sin θ x Ff. Horizontal is torque for g. Is that correct? If so, is one positive and the other negative...
  5. K

    Ladder leaned against a wall; forces

    Ok, I'll pick the bottom of the ladder, where it meets the ground. For force of g: T = mg x 2.5cos θ For force of FNwall: T = ? x 5cos θ For the other two forces, T = 0 I'm not sure where that brings me, though.
  6. K

    Ladder leaned against a wall; forces

    Homework Statement There is a 5m ladder leaned against a wall, making an angle of θ with the ground. The ground is rough (getting at friction), and the wall is frictionless. Here's an ASCII attempt: |\ |..\ |...\5 |...\ |...θ\ We want to make a force diagram for the ladder, then find the...
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