Mechanical Engineering: Particle Equilibrium (11 of 19) Why are Pulleys a Mechanical Advantage?
Michel van Biezen・2 minutes read
Pulleys provide mechanical advantage by redirecting and reducing the force needed to lift an object, with each additional pulley in a system further decreasing the required force. The Atwood machine lifts a 100 Newton object with 100 Newtons of force, while a system with four pulleys reduces the force to 25 Newtons, needing a 4-meter pull to lift the object 1 meter.
Insights
- By using pulleys, the force required to lift an object can be reduced significantly, with more pulleys leading to a further decrease in the force needed.
- The Atwood machine demonstrates that in a simple pulley system, the force required to lift an object remains the same as its weight, but as more pulleys are added, the force needed decreases proportionally, showcasing the mechanical advantage gained through pulley arrangements.
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Recent questions
How do pulleys provide mechanical advantage?
By redirecting or reducing force needed for lifting.
What is an Atwood machine?
A simple pulley system with equal force requirements.
How does a two-pulley system reduce force?
By distributing the force equally between sides.
How does a three-pulley system further reduce force?
By dividing the load into smaller increments.
How does a four-pulley system reduce force even more?
By requiring less force per rope.
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Summary
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"Pulleys: Efficiently reducing force for lifting"
- Pulleys are used to gain mechanical advantage in two ways: redirecting the force required to lift an object and arranging pulleys to reduce the force needed to pull an object up.
- In a simple pulley arrangement called the Atwood machine, where an object weighing 100 Newtons is lifted, the force required to pull it up is also 100 Newtons.
- In a second pulley system with two pulleys, the force required to lift the 100 Newton object is reduced to 50 Newtons, with each side of the pulley carrying 50 Newtons of force.
- A third pulley system with three pulleys further reduces the force needed to lift the object to 33 Newtons, with each rope carrying 33 Newtons of force.
- In a fourth pulley system with four pulleys, the force required to lift the 100 Newton object is reduced to 25 Newtons, with each rope carrying 25 Newtons of force, requiring a 4-meter pull to lift the object 1 meter.
