Non-Physics Major Needs Physics Help

[Muirghiel]

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.

 

[LowlyPion]

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.

Welcome to PF.

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

 

[baba89]

I understand that physics can be a challenging subject for non-physics majors. I commend you for taking the initiative to seek help and clarify your understanding. Here are my responses to your questions:

1. The difference between a compound lever and a multiple lever lies in their design and function. A compound lever is made up of multiple levers connected together, with each lever having its own fulcrum. This allows for a greater mechanical advantage, meaning that a smaller effort can move a larger load. In contrast, a multiple lever is made up of multiple loads and efforts, with the load of one lever becoming the effort of another. This allows for a trade-off between force and distance, meaning that a larger effort is required to move a larger load, but the distance moved is smaller. A real-world example of a compound lever is a pair of pliers, where the handles act as levers. A real-world example of a multiple lever is a wheelbarrow, where the handles act as levers and the load is the weight in the wheelbarrow.

2. Yes, a wheel can be thought of as a type of lever, with the axle acting as the fulcrum. When the effort is applied on the axle, it is a third class lever because the effort is closer to the fulcrum than the load. When the effort is applied on the outer part of the wheel, it is a second class lever because the load is closer to the fulcrum than the effort. The mechanical advantage of a lever depends on the ratio of the effort arm (distance from the fulcrum to the effort) to the load arm (distance from the fulcrum to the load). For a third class lever, the mechanical advantage is always less than 1, meaning that a larger effort is required to move a smaller load. For a second class lever, the mechanical advantage is always greater than 1, meaning that a smaller effort can move a larger load.

3. The mechanical advantage of a pulley system is determined by the number of ropes involved. This is because each rope supports a portion of the load, reducing the overall force required. The ideal mechanical advantage is equal to the number of supporting ropes, meaning that a pulley system with 4 ropes will have a mechanical advantage of 4. The difference between a change in direction and an actual rope is that a change in direction does not support any of the load, while an actual rope