Simple Machines (4 of 7) Pulleys; Calculating the Amount of Work Done

For the pulley simple machine shows how to calculate the amount of work done when raising an object and why simple machines do not make your work easier!

A simple machine is a mechanical device that changes the direction and the magnitude of a force. In general, they can be defined as the simplest mechanisms that use mechanical advantage (also called leverage) to multiply force. Usually the term refers to the six classical simple machines that were defined by Renaissance scientists: the lever, the wheel and axel, the inclined, the screw, the wedge and the pulley. Simple machines do not make work easier, less input force may be needed but the force must be applied over a longer distance.

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[maxblack]

your channel is literally saving my physics grade right now, cant thank you enough!
im stalking all your videos about work, energy, and power

[ericny]

It may be the same amount of "work" but it is a LOT easier to do. You may have to pull the rope 4 times longer, but afterwards you would be no where near as tired as if you didn't use the pulley.

[picklechinazzboi]

Thanks bro I thought I seriously was going to fail for the first time in science but you helped me out 😀👍

[malcolmboyley]

Thank you for a well presented video so concise and easy to understand.

[qgtdrgx]

Thank you so much. I watched loads of videos and this one really helped me to understand.
It does make it seem easier. It feels easier to do it in small blocks sort of than in one big go though in the end it's the same work, you might not feel as tired and exhausted.

[janet]

Your video was very helpful. Thank you. Although it's the same amount of work, at least you won't rip your muscles off of the bone while lifting.

[Kayayuh]

If I am not given a distance, but a load force, effort force, # of supporting ropes, and # of Pulleys, how can I calculate Work?

[sanbhai]

Thanks, I am having physics exam today.

[blackopal]

It still makes work 'easier', though. If you have an object you can't lift because it is too heavy, say you need to lift it 1 foot. if you add 4 pulleys, now you can lift it, to accomplish the goal, yes, you now have to pull the rope 4' as opposed to 1', but you choke up on the rope a couple times, and you are successful and not injured. without the pulleys, you can't do it, or break your back. Pulleys made your work easier by spreading the Joules out into manageable chunks.

[sonar]

it comes down to strength vs endurance. if you look at any crane on a construction site you see that they all use a pulley system. why? because it comes down brute strength vs endurance. my arms can pull a lighter weight far longer than a heavier weight. it's like riding a 10 speed up a hill. if the work is the same then why not leave it in the higher gear? you always shift to a lower gear because it is easier even though you have to pedal twice as much. This is the problem with doing things on paper. as I said strength vs endurance or work vs effort. while mathematically the "work" is the same, the "effort" involved in the work is not. from a physics stand point it is the same from a physical stand point it is not. but, what do I know I'm just an uneducated idiot.

[brandonwombacher]

Simple Machines don't make work easier, they trade force for distance or distance for force

[Thisssssssssss]

Nice video!  However your claim that using a pulley does not make things easier is just wrong and I think distracts from the good point that you are trying to make.  It's ignoring what the word "easy" actually means - it is not the equivalent of the physics definition of "amount of work done".  For example, it is much easier for most people to pick up and move 20 10kg blocks one at a time than to pick up and move 1 200kg block.  Your students are right to say simple machines make things easier, and you are wrong to say that they don't.  If they didn't, they would never have been invented and they would never be used.  Other than that, good work on the video!

[motomedic]

Work may be the same. Of that there is no argument. However, the FORCE I need to be capable of to move the FORCE being moved is NOT the same. If I am a puny physics student that can only lift 40 N then I cannot move the 90 N force. But my overweight brain figures out that I can, with the aid of a machine, move the excessive weight using only about half of my capability. SCORE!