Simple pulley question- single fixed

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In summary: ITIn summary, for a single fixed pulley system with equal length ropes and equal masses on both sides, the system will be in static equilibrium if there is no friction. However, if there is no friction and a small incremental weight is added to one side, the system will experience non-zero acceleration and eventually one side will completely fall. It is difficult to achieve perfect equilibrium in practice due to the challenges of setting up a frictionless pulley system with exactly equal masses on both sides.
  • #1
gloo
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for a single fixed pulley system :

1. on both sides -equal length ropes
2. equal masses to balance each other (static)
3. ignoring weight of the ropes and friction (pulley, rope, air etc..)

..if no friction- can it be assumed that the next incremental bit of weight on either side- (say a big fly lands on one side of the mass) will tip the scale so that one side completely pulls down the other
 
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  • #2
gloo said:
for a single fixed pulley system :

1. on both sides -equal length ropes
2. equal masses to balance each other (static)
3. ignoring weight of the ropes and friction (pulley, rope, air etc..)

..if no friction- can it be assumed that the next incremental bit of weight on either side- (say a big fly lands on one side of the mass) will tip the scale so that one side completely pulls down the other
You don't have to assume it. You can work it out. If the weights are not equal, there is a net force so there will be non-zero acceleration: F=(m1-m2)g = m1a. If there is non-zero acceleration, the distance that the system will move in time t is s = at^2/2 so one side will completely fall eventually.

It should not be surprising that a fly would cause one side to fall. The real difficulty in practice would be to set up a frictionless pulley with equal masses on both sides so that they were exactly balanced.

AM
 
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1. What is a simple pulley?

A simple pulley is a basic machine that consists of a grooved wheel and a rope or belt. It is used to change the direction of a force, making it easier to lift or move heavy objects.

2. How does a single fixed pulley work?

A single fixed pulley works by changing the direction of the force applied to an object. The rope or belt is looped around the pulley, and as one end is pulled down, the other end goes up, lifting the object. The pulley itself does not reduce the amount of force needed, but it changes the direction of the force, making it more manageable.

3. What is the purpose of a single fixed pulley?

The purpose of a single fixed pulley is to make it easier to lift or move heavy objects. By changing the direction of the force, the pulley reduces the amount of effort required to lift the object. It is commonly used in lifting systems, such as those used in construction and transportation.

4. What are the advantages of using a single fixed pulley?

The main advantage of using a single fixed pulley is that it reduces the amount of effort needed to lift heavy objects. It also allows for a more controlled and precise movement of the object. Additionally, pulleys are simple machines that are easy to set up and use.

5. Are there any limitations to using a single fixed pulley?

Yes, there are some limitations to using a single fixed pulley. One limitation is that it does not reduce the amount of force required to lift an object, it only changes the direction of the force. Also, a single fixed pulley can only be used to lift objects vertically; it cannot be used to move objects horizontally. Finally, it is not as efficient as other types of pulleys, such as compound and block and tackle pulleys, which are able to reduce the amount of force needed to lift heavy objects.

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