Pulley Systems

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Written by Chen Jian Xun Design and edit by Rebecca Sopacua

Typesof ofPulleys PulleysSystems Systems Types

Fixed

Moveable Compound Black & Tackle

Pulleys come in many shapes and sizes, and is used to change the direction of an applied force to lift weight or objects. The reason pulleys allows you to lift something heavy with less effort is due to the tension in the ropes and its ability to redirect forces to amplify the input force or to reduce the weight of the object.

Written by Chen Jian Xun Design and edit by Rebecca Sopacua

For example, the image on the left shows a compound pulley consisting of two pulleys. The image show a 10N weight being lifted but only requiring 5N as input force, this because there are two upwards force in the two sections of the rope caused by the tension in the ropes and the weight of the object is equally divided amongst the two section which is why it will only require 5N of force to lift the 10N weight.

Or another way of looking at it is that the end of the rope along with the rope looped on the top right pulley is exerting a downwards force on the surface that they are hanging from instead of exerting all the force of the object on you.

You can stack as many pulleys as required to lift an object like in the image at the right and the more sections of rope that are exerting an upwards force from the object, the less input force is needed.

There is a tradeoff when using pulley. For every pulley you add, you would have to pull further to lift an object to the same height as compared to not using a pulley. Basically you trade distance traveled by the lifted object for less force required to lift the object.

Written by Chen Jian Xun Design and edit by Rebecca Sopacua

SOURCES: SOURCES: Fig.1 https://www.google.com/imgres?imgurl=https%3A%2F%2Fengineeringdi scoveries.com%2Fwp-content%2Fuploads%2F2020%2F01%2FUntitled-1GD FG-scaled.jpg&imgrefurl=https%3A%2F%2Fengineeringdiscoveries.com%2 F2020%2F01%2F08%2Ftypes-of-pulleys-systems%2F&tbnid=ivTv24LkAH_ mtM&vet=12ahUKEwi8zsbf2KjqAhVIyZQKHb5KAfwQMygNegUIARDqAQ..i& docid=EpmdpYRHNY0_9M&w=2560&h=1320&q=pulleys%20&safe=strict&cl ient=ms-android-samsung&ved=2ahUKEwi8zsbf2KjqAhVIyZQKHb5KAfwQ MygNegUIARDqAQ

Fig.2 https://www.google.com/imgres?imgurl=https%3A%2F%2Fi.pinimg.com %2Foriginals%2F59%2F0a%2F31%2F590a310723b6659d8d9b2c0e23d8763a.p ng&imgrefurl=https%3A%2F%2Fwww.pinterest.com%2Fpin%2F1216676274 09755222%2F&tbnid=bkifd3YzCWCPbM&vet=12ahUKEwj84M-W3KjqAhWF GCsKHU8XC8kQMygBegUIARD5AQ..i&docid=6C3ABGvazoOMcM&w=273&h =300&q=compound%20pulleys&safe=strict&client=ms-android-samsung&v ed=2ahUKEwj84M-W3KjqAhWFGCsKHU8XC8kQMygBegUIARD5AQ

Fig.3 https://www.google.com/imgres?imgurl=http%3A%2F%2Fwww.tex22.info %2Frm%2Fenglish%2Frobotics3%2Fvex%2Fstudent%2FContent%2FResour ces%2FImages%2FArchived%25202%2FPulley04.png&imgrefurl=http%3A% 2F%2Fwww.tex22.info%2Frm%2Fenglish%2Frobotics3%2Fvex%2Fstudent% 2FContent%2FCurriculum%2520-%2520Robotics%2FRobo%25203%2FMod %25201%2520-%2520Simple%2520Machines%2F10_Pulleys%2520-%2520I ntroduction.htm&tbnid=eE4Pexq9Lj1CtM&vet=12ahUKEwj84M-W3KjqAhW FGCsKHU8XC8kQMygJegUIARDKAQ..i&docid=AlV0V8VSwapz-M&w=2377& h=1853&q=compound%20pulleys&safe=strict&client=ms-android-samsung &ved=2ahUKEwj84M-W3KjqAhWFGCsKHU8XC8kQMygJegUIARDKAQ

Written by Chen Jian Xun Design and edit by Rebecca Sopacua