Stuck tractor - ways to lift?

[RoyJackson]

If you read post #17 (of this thread), you'll know the OP got his tractor out...so all this discussion of pulleys, leverage and mechanical advantage...or a wrecker...is moot for this thread.

 

[RickB]

If you read post #17 (of this thread), you'll know the OP got his tractor out...so all this discussion of pulleys, leverage and mechanical advantage...or a wrecker...is moot for this thread.

Roy, you must have forgotten that you are on TBN; the cyber-capital of moot.

 

[bcp]

There should be a lighthouse on Moot Point so it can be avoided.



Bruce

 

[SPYDERLK]

If you read post #17 (of this thread), you'll know the OP got his tractor out...so all this discussion of pulleys, leverage and mechanical advantage...or a wrecker...is moot for this thread.

Demerits to all who posted since - regardless of relevance to the situation described.
larry

 

[sldva00]

Sorry Roy, moot or not, I think this might clear things up a little.

Using a single pulley all depends on where the pulley is placed.

1. If pulley is placed on tree, then yes, it will take the same amount of force to move the tractor. The tree will experience twice the amount of force, but the tractor and towing vehicle will experience the same amount of force. If tractor weighs 2000 lb, then the tree would exert 4,000 lb of force while the tractor and towing vehicle would exert 2000 lb.

2. If pulley is placed on tractor, then it will take half the amount of force to move it. The tractor will exert its 2000lb force, but the tree and towing vehicle would only need to exert 1000 lb of force.

The force at the pulley is divided into the lines coming out of it.

 

[RoyJackson]

Sorry Roy, moot or not, I think this might clear things up a little.

Nothing to be sorry about...info is good if anyone gets stuck and has access to the equipment and fixed objects close enough to use.

 

[kday64]

The Mechanical Advantage (MA) for simple pulleys equals the number of times the rope changes direction.

Simple pulleys are those where internal friction is assumed small enough to be ignored and the cable is assumed to be non-elastic. Additionally there can only be one mounting point for each side of the pulley system.

Case #1: 1 pulley -> MA = 1 -> direction of force reversed. -> force pulled equals force applied at both mounting points -> tension in line equals force pulled on rope.

Case #2: 2 pulleys -> MA = 2 -> force exerted on pulley mounting points equals twice the tension in the line.

Remember MA has it's disadvantages. If the MA of a simple pulley system is 10 and you need to pull an object 20 feet, you will need 200 feet of rope. However the force exerted on the mounting equals 10 times the tension of the line.

Multiple mounting points can only lesson a systems MA.

~Kevin

 

[chopped]

There should be a lighthouse on Moot Point so it can be avoided.



Bruce

GOOD ONE>>:thumbsup::thumbsup:

 

[pat32rf]

The MA fun starts when you add ANOTHER piece of cable and pulley to the equation. Then you get 4000lb of force from one 1000lb winch and two pulleys..