People think pulleys increase pulling power.

MOguy

Explorer
It is not the Rope moving around the pulleys that causes mechanical advantage. It is the distance the rope moves between pulleys that causes mechanical advantage.
 

MOguy

Explorer
Anyone that has been on this forum very long knows you too well to be bothered, you'll come up with some excuse why it's wrong and your right just like you do with any logical explanation presented to you. I got nothing better to do at the moment than exchange BS with you for entertainment, but if I'm home and have access to my winch and tackle, hell I got much better ways to spend my time than proving something I don't need convincing of.

You apparently got time on your hands and access to your gear, go measure it the right way yourself. Measure it a bunch of different ways, heck cover your bases. It might even improve our opinions of you for future discussions on physics. If this is really something you are interested in, you would be out there now checking it out to satisfy your own questions and not have to wonder if we are pulling your leg.
are you too close minded and lazy to learn. Don't you have 10 minutes to prove me wrong?
 
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robert

Expedition Leader
Now you're just being obtuse. Yes, the pulley attached to the vehicle moves along with the vehicle- that does not change your mechanical advantage. Adding more pulleys into the system does increase the amount of line needed and the distance that line must be moved overall (see 3:23 in the first video where he explains this- I think this is where you are getting confused).

Try watching this video and see if it helps, start are 0:40:

If that doesn't help then here's one with cartoon characters in it. The female character in it actual sets up a 3:1 system like you are disputing.

Edited to post correct video link.
 
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MOguy

Explorer
Now you're just being obtuse. Yes, the pulley attached to the vehicle moves along with the vehicle- that does not change your mechanical advantage. adding more pulleys into the system does increase the amount of line needed and the distance that line must be moved overall.

Try watching this video and see if it helps, start are 0:40:

If that doesn't help then here's one with cartoon characters in it. The female character in it actual sets up a 3:1 system like you are disputing.
Now you're just being obtuse. Yes, the pulley attached to the vehicle moves along with the vehicle- that does not change your mechanical advantage. Adding more pulleys into the system does increase the amount of line needed and the distance that line must be moved overall (see 3:23 in the first video where he explains this- I think this is where you are getting confused).

Try watching this video and see if it helps, start are 0:40:

If that doesn't help then here's one with cartoon characters in it. The female character in it actual sets up a 3:1 system like you are disputing.

Edited to post correct video link.
Is there or is there not a pulley moving within each one of these systems that gains mechanical advantage? When I say moving I don't mean rotating, I mean moving in the direction of the load.
 

MOguy

Explorer
Just think about it. The cable cannot change length, it's not possible. The only thing that moves or changes is the positions of the pulleys. In order for the pullies to change position they have to move and in order for them to move they had to be located on the load which is moving or within the rigging.
 

robert

Expedition Leader
Yes, the pulley attached to the vehicle is moving along with the vehicle if that is what you are asking. That doesn't change the fact that you have a 3:1 mechanical advantage in the previous picture.

I'll try another video for you but honestly, at this point I don't know how to explain this to you. if this doesn't work then please go to your local high school, tech school or college and ask to speak to one of the physics instructors.
 

Factoid

Three criminal heroes
Whoever posted the Jeep and tape measure, you missed a measurement. There is two feet of CABLE movement at the pulley.
 

robert

Expedition Leader
No doubt, all I can say at this point is to remember that vehicle recovery is an inherently dangerous activity that has the potential to cause injury or death and as such should not be attempted by folks who don't have some training and understand what they are doing. :eek:

I hate these new smiley things.
 

MOguy

Explorer
Yes, the pulley attached to the vehicle is moving along with the vehicle if that is what you are asking. That doesn't change the fact that you have a 3:1 mechanical advantage in the previous picture.

I'll try another video for you but honestly, at this point I don't know how to explain this to you. if this doesn't work then please go to your local high school, tech school or college and ask to speak to one of the physics instructors.

Let's keep it simple and go step by step.

We agree that the pulley has to be moving within the system or on the load to game mechanical advantage.

If that is the case can the second picture in the Jeep tree diagram where it shows the cable going from the winch on the Jeep to a pulley on the tree gains no mechanical advantage?

I swear I am not trolling, I'm not trying to be condescending or any of that I am trying to answer a question.

In the process of doing that I became confused by the diagram of the Jeep / tree and what people are saying. I had to show for myself whether or not it was true.


The ultimate question I want to answer is if I put my pulling Force within the rigging or the system how much mechanical Advantage will that gain.
 

MOguy

Explorer
After deep thinking I am baffled. I asked my 3 year old daughter. She said ”Daddy, you are such a **************. The rope gets shorter or longer because it winds up on the winch”. Kids say the darndest things..
Actually the amount of cable on the drum will affect the pull but in a different manner
 

robert

Expedition Leader
"If that is the case can the second picture in the Jeep tree diagram where it shows the cable going from the winch on the Jeep to a pulley on the tree gains no mechanical advantage? "

That is a simple 2:1 MA system. The simplest way to figure it out is to count the lines although as the video with the Hispanic guy shows, there are more complex ways to set these up.
 

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