Thats a good idea Trout... Will be replacing winch on boat trailer(with an electric, something to do with my age) so can use that instead...
Thanks Mate...
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Mod hat on.
Gentlemen, either agree to disagree or get a room. Either way keep the personal shots out of the discussion.
Back to your regular programing.
Here is an example of a fixed pulley (on the left) that has no mechanical advantage, providing the force is applied by a winch that remains at a fixed distance from the pulley.
https://www.aulro.com/afvb/images/im...017/07/138.jpg
Where winching your own vehicle differs is that the winch and the load are moving relative to the pulley, therefore getting a MA of 2. The second illustration shows a moving load and pulley. Both the winch and the cable anchor are attached to the same object. Where a certain person is hanging up is that a winch can not tell the difference between a moving anchor and a moving load. The winch does not consult a GPS to determine if it is moving. A winch cares not if a tree is pulled over by a stationary vehicle or a tree is pulling a vehicle out of a bog. All it knows is that the pulley moves relative to the winch and load combined. A vehicle using a rope passing through a pulley and returning to the vehicle is a moving pulley problem not a fixed pulley problem. The third image is also showing a MA of 2, the second pulley is just a stand in for a winch or capstan and adds no mechanical advantage.
Simple physics. [bigsmile1]
In the third image if the weight is the vehicle and the winch on the vehicle is at the end of the red arrow I would have thought that is a MA of 3 versus a straight pull.
The effort is being spent over 3 times the distance.
I only did physics and applied maths so don't go too hard!
cheers, DL
The Chicks love 'em though, so manly, and look at those really cool tuff cut of sleeves. A bloke could never get snot that far up his arm.
In the third pic MA is determined by "the number or parts of rope supporting the MOVING block" so the MA is 2 the other block is used to change the direction of the pull, e.g. if you were behind the load/vehicle that was being winched and placed a snatch block to a tree ahead of the winched vehicle and back to your winching vehicle, if a snatch block is not moving with the load, (in other words to "Advantage") then the fixed block is only changing direction of the pull, in this case to "Disadvantage".
If you look at a large crane with a bunch of pulleys and a large hook and count the number of ropes supporting that block of pulleys and hook you will have the MA of that setup, the lead rope which is pulled to disadvantage (opposite direction that the load is moving in) is not to be considered as part of the supporting ropes, Regards Frank.