Pulleys: Why would my calculated work output be higher than my work input?

In summary, the conversation discusses a Physics lab experiment on determining the mechanical advantage and efficiency of pulley systems. The calculated work output is higher than the work input, leading to a high efficiency value and the individual is trying to identify the source of error. The data tables and lab procedure are attached. It is suggested that the error may be due to incorrect measurement, specifically not including the mass of moving pulleys in the total load mass.
  • #1
veganazi
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0

Homework Statement


The experiment in my Physics lab today was to determine the mechanical advantage and efficiency of various pulley systems. My calculated work output is higher than my work input, which is causing an abnormally high value for efficiency, and I am attempting to find the source of error. I have attached my data tables and a copy of the lab procedure.

Homework Equations


work output = (weight of load) * (height lifted)
work input = (force measured) * (distance moved)

The Attempt at a Solution


I guess it would be error in measurement, though I am unsure of how this could have happened.
 

Attachments

  • pulley lab tables.xls
    33 KB · Views: 390
  • pulleys procedure.pdf
    102.1 KB · Views: 1,465
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  • #2
Did you remember to include the mass of any pulleys that moved along with the load in the total load mass? (See step 7 instructions).
 

1. Why is my calculated work output higher than my work input?

This could be due to a number of factors, such as friction and inefficiencies in the pulley system. Friction can cause some of the energy to be lost as heat, resulting in a lower work input and a higher work output. In addition, the pulley system may not be perfectly efficient, meaning that some of the input energy is lost as well.

2. Can the number of pulleys affect the calculated work output?

Yes, the number of pulleys in a system can affect the calculated work output. Generally, the more pulleys there are, the greater the mechanical advantage and the higher the calculated work output. However, this also depends on the efficiency of the pulleys and the amount of friction in the system.

3. Is it possible for the work output to be lower than the work input in a pulley system?

Yes, it is possible for the work output to be lower than the work input in a pulley system. This could be due to inefficient pulleys or high levels of friction, which can cause energy to be lost and result in a lower work output. It is important to take into account these factors when calculating the work output of a pulley system.

4. How can I increase the work output in a pulley system?

One way to increase the work output in a pulley system is by using more pulleys. This increases the mechanical advantage of the system and can result in a higher work output. Additionally, using more efficient pulleys and reducing friction in the system can also increase the work output.

5. What are some real-world applications of pulleys?

Pulleys have many real-world applications, such as in elevators, cranes, and construction equipment. They are also commonly used in exercise equipment, such as weight machines and resistance bands. In addition, pulleys are used in many mechanical systems, such as engines and vehicles, to transfer power and increase mechanical advantage.

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