I have a question about pulley

  • Thread starter adamwojciech
  • Start date
  • Tags
    Pulley
In summary, a fixed pulley requires the same amount of force as the weight being lifted, while a movable pulley only requires half the force. For a "reversed movable" pulley, where the weight is hanging from the free end of the rope, it would take twice the force of the weight being lifted to lift it. This type of pulley is commonly used in block and tackle or mobile crane setups.
  • #1
adamwojciech
1
0
Hi

I have a question about pulley.
There is fixed pulley: http://en.wikipedia.org/wiki/File:Polea-simple-fija.jpg http://en.wikipedia.org/wiki/File:Polea-simple-fija.jpg where you need to use e.g. 100N to lift 100N.
There is moveable pulley: http://en.wikipedia.org/wiki/File:Pulley1a.svg http://en.wikipedia.org/wiki/File:Pulley1a.svg where you need to use e.g. 50N to lift 100N.

Question: How does "reversed moveable" pulley look like, i.e. the one where I need to use 200N to lift 100N? I need it for my home gym.

Thanks
Adam
 
Physics news on Phys.org
  • #2


adamwojciech said:
Question: How does "reversed moveable" pulley look like, i.e. the one where I need to use 200N to lift 100N? I need it for my home gym.
On the image for moving pulley, picture weight hanging from the free end of the rope instead of from the moving pulley. It will take 200N of downward force on the moving pulley to lift the 100N weight in that case.
 
  • #3
Google images for a block and tackle, or a mobile crane block. Once you see one rigged up your answer should be self evident.
 

What is a pulley?

A pulley is a simple machine that uses a wheel with a groove in it and a rope or cable to change the direction or magnitude of a force.

How does a pulley work?

A pulley works by using the principle of mechanical advantage, which means that it can make it easier to lift or move heavy objects by distributing the force needed over a longer distance.

What are the different types of pulleys?

There are three main types of pulleys: fixed pulleys, movable pulleys, and compound pulleys. Fixed pulleys are attached to a structure and change the direction of the force. Movable pulleys are attached to the object being moved and can increase the mechanical advantage. Compound pulleys combine fixed and movable pulleys to increase both the direction and magnitude of the force.

What are some examples of pulleys in everyday life?

Pulleys can be found in many everyday objects, such as flagpoles, elevators, cranes, and window blinds. They are also used in exercise machines, sailing equipment, and even some types of sewing machines.

How are pulleys used in science and engineering?

Pulleys are used in many scientific and engineering applications, such as in construction, transportation, and manufacturing. They are also used in experiments to demonstrate principles of physics and engineering, and in research and development for creating new technologies.

Similar threads

Replies
9
Views
1K
Replies
4
Views
2K
Replies
14
Views
10K
  • Introductory Physics Homework Help
Replies
8
Views
2K
Replies
7
Views
1K
  • Engineering and Comp Sci Homework Help
Replies
3
Views
2K
  • Introductory Physics Homework Help
Replies
5
Views
1K
Replies
11
Views
2K
Replies
3
Views
4K
Back
Top