text: friction & pulley? hi, r there any forces of friction that can affect the mechanical advantage of a pulley? can you explain, please? thank u very much for any help first we have to go over what is the advantage of a pully.  a pully destrebutes the forces around the pully, so that you do not have the full force in one single point.   this advantage is present weather the pulley turns or not.  for example rock climbers will wrap a rope around a tree to help pull somebody up a cliff.    now a rock climber would love to use a pulley instead of a tree but the point is the advantage is still there with the tree.   so from this you can get that the friction of the base holding the center of the pulley would effect the advantage of the pulley.   but you would have to also say what do you want?  the more friction there is the harder it is to pull but like in the case of the tree and the rock climber, if he stops pulling the other climber will not fall.  as apposed to having a pulley where the rock climber will be easy pulling up but if he stops pulling the rock climber will fall down.   so it comes down to what is the advantage of having a pulley.    hope this helps -david-