They did. You just weren’t paying attention, and it was only one day of the class. And it was one of the easy exam questions, so you didnt remember struggling on it.
Comment on xkcd #3087: Pascal's Law
kayzeekayzee@lemmy.blahaj.zone 1 month ago
WHAT??? Why didn’t they teach me this in physics school???
blarghly@lemmy.world 1 month ago
14th_cylon@lemm.ee 1 month ago
it is really one of the basic physic principles that is taught in the high school, so i have no idea what kind of physic’s school would not teach that.
phar@lemmy.ml 1 month ago
School of Christian Physics
lefaucet@slrpnk.net 1 month ago
This the class where they teach us about how many angels can dance on the head of a needle? I couldn’t tell you how many times I’ve used those formulas
OmegaLemmy@discuss.online 1 month ago
They didn’t?
ColeSloth@discuss.tchncs.de 1 month ago
How do you think vehicle brakes had always worked? You think lightly pushing your foot on a pedal brings the 4,000 lb car to a stop with farts and whistles?
Ironfacebuster@lemmy.world 1 month ago
Well depending how close to going out your brake booster pump is, it very well could be powered by farts and whistles!
ReluctantMuskrat@lemmy.world 1 month ago
The dude is clearly underestimating my farts.
grue@lemmy.world 1 month ago
They certainly should’ve; it’s just a consequence of how pressure is force divided by area.
Here’s an analogy that might make it feel less weird: you know how you can reduce the force needed to lift a heavy weight by using a lever and making the lever arm longer? This is the same kinda deal, except that instead of varying the length of the lever arm you’re varying the diameter of the hydraulic pistons.
You don’t get it for free, of course: just like how you have to push the long end of the lever a longer distance to lift the weight a shorter distance, in a hydraulic system you have to press the plunger further down the small-diameter piston to move the plunger in the large-diameter piston up a smaller amount.
(I thought of mentioning pulley systems as an analogy too, but of these three varieties of gaining mechanical advantage I find pulley systems to be the most confusing, LOL.)
Tja@programming.dev 1 month ago
Another example: gears. You have a small wheel moving a large wheel trading speed for torque (or vice versa).
kopasz7@sh.itjust.works 1 month ago
No, you’re right, pulleys are mechanical witchcraft, I tell you!
Flocklesscrow@lemm.ee 1 month ago
Archimedes over here with his bigass lever
FooBarrington@lemmy.world 1 month ago
Love his famous quote:
kattfisk@lemmy.dbzer0.com 1 month ago
A simple experiment to get an intuitive understanding of pulleys:
Take a piece of string and hold one end in your right hand, then hold your left hand higher and let the string run over it and hang down.
Now as you move your right hand up or down, the free end will move the same distance. But if you move your left hand up or down, the free end must move twice the distance, because you have string on either side of the hand that must both move that distance. So you are amplifying the movement, getting twice the movement at half the force.
If instead you wanted to amplify the force, as in a pulley, then stand on the free end of the string (so it’s no longer free) and pull down with your right hand. You are now amplifying the force exerted on your left hand, because it moves only half the distance of the right, so you get double the force. And this is exactly how a pulley works. Add more loops to get even more force at the cost of even more movement.
I figured this out while playing with the cats, and it made pulleys just make sense. Hopefully it can do the same for someone else :)