Work Input vs Work Output in Pulley Systems

[moomoocow]

hello again,
i know that in an ideal pulley system, work input is equal to work output..however in reality, that is not possible due to friction

but what confuses me is that within what percentage is work input=work output?
how are we supposed to find the percentage?

thank you!

 

[OlderDan]

In a real pulley, the friction results in a torque that opposes the rotation of the pulley. If you know the torque and the angular displacement you can calculate the work done by friction. The work output is the work input minus the work done by friction.

 

[kyle8921]

Hello there,

You are correct, in an ideal pulley system, the work input is equal to the work output. However, in reality, there are various factors such as friction, air resistance, and energy loss that can affect the efficiency of the pulley system. This means that the work input will always be slightly higher than the work output.

To determine the percentage of efficiency in a pulley system, we can use the formula: Efficiency = (Work Output / Work Input) x 100%. This will give us a percentage that represents the amount of work that is actually being transferred from the input to the output.

For example, if the work input is 100 Joules and the work output is 90 Joules, the efficiency would be (90/100) x 100% = 90%. This means that only 90% of the input work is being transferred to the output, while the remaining 10% is lost due to friction and other factors.

I hope this helps clarify the concept of work input vs work output in pulley systems. Keep in mind that the efficiency percentage will vary depending on the specific conditions and design of the pulley system.