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Homework Help: Non-Physics Major Needs Physics Help!

  1. Oct 2, 2008 #1
    Hi, I'm a new member, and my problem is that I'm new to physics. I'm a non-physics major, taking a physics course to fill in a science credit. This is the most basic of basic courses. I'm reviewing for a test and will post questions accordingly.

    If you want symbols, variables, and data, you'll have to be patient with me. Because I do not understand any of this.

    1. What is the difference between a compound lever and a multiple lever? I was told a multiple lever is made up of loads and efforts where the load of one lever becomes the effort of another lever. But I don't understand how that would work in a practical setting, and even if it did, how is that different from a compound lever? What is a compund lever? I must be able to give real-world examples of each.

    2. Assume that a wheel is a type of lever, with the axle being the fulcrum. If you put the effort on the axel, does it become a third class lever, moving the outer portion of the wheel? What about when you put the effort on the outer part of the wheel? Is that a second class lever? My professor insists that we think of the wheel-and-axel as a lever. It makes very little sense to me. And for each class of...wheel? We have to identify if we gain a Mechanical Advantage (MA) or a Speed Advantage (SA).

    3. How does one determine the mechanical advantage of a pulley system? My teacher says it has to do with how many ropes are at work. "The Ideal Mechanical Advantage (IMA) of a pulley system is equal to the number of supporting ropes."

    If you have a long rope, it is divided among the pulleys into smaller ropes. But what's the different between a change in direction, and an actual rope?

    I have more questions. Lots of them. My test is on Tuesday and I'm trying to get as much help as I can.
     
  2. jcsd
  3. Oct 2, 2008 #2

    LowlyPion

    User Avatar
    Homework Helper

    Welcome to PF.

    Perhaps this will help?
    http://en.wikipedia.org/wiki/Pulley#Types_of_systems
     
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