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This video is about elastic and inelastic collisions in 1D, 2D and 3D - and how the collision of conservation of energy with conservation of momentum, plus a secret direction, results in a completely predetermined behavior for most collisions.
REFERENCES
1D Collision Calculator:
http://hyperphysics.phy-astr.gsu.edu/hbase/col1d.html#c1
Elastic collision of spheres Wolfram
https://demonstrations.wolfram.com/ElasticCollisionsOfTwoSpheres/
Oblique collisions of two 2D spheres
https://iopscience.iop.org/article/10.1088/1361-6404/aab330
Ballistic Pendulum
http://hyperphysics.phy-astr.gsu.edu/hbase/balpen.html
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Minute Physics provides an energetic and entertaining view of old and new problems in physics -- all in a minute!
Created by Henry Reich
Making things that look confusing make sense is one of the beauties of Physics
@IshaanSaha-u4v Says:
https://youtu.be/bSVfItpvG5Qt=31 This is true in every universe not only in our universe.
@raffimolero64 Says:
My favorite thought when making a bouncing balls simulation was figuring out this property based on "Reference frames" and "Relativity" (air quotes because i didn't fully understand)
basically, all these scenarios are the same:
- 2 objects are hurling towards each other (object A has velocity (x, 0), object B (-x, 0))
- one object is hurling at 2x speed towards the other (A: (2x, 0), B: (0, 0))
- they are hurling towards each other + some "reference velocity" (A: (x+h, k), B: (x-h, k), reference velocity is (h, k))
and i found that no matter what you did to the 2 spheres, bouncing off of another sphere could always be imagined as if bouncing off of a flat surface (because they can't rotate)
pretty fun stuff.
@jsytac Says:
You cannot subtract an Energy from a Momentum.
@NovaRuner Says:
So….for the sake of the math, and thought experiment. We are ignoring the possibility of one or both objects being damaged, or breaking in any way during the collision? I am just wondering…
In real life. Some times two colliding objects are durable enough to survive and bounce off each other. And other times… not so much. I know that simplifying things for the sake of the hypothetical situation is important. But it is also important to remember that other possibilities exist outside of the simple model.
@tyrport Says:
If these came out daily, I would watch daily. A true gem.
@Daraen-k7l Says:
if collisions along with rotational ones are particularly determined then fluid dynamics in principle at least could be deterministic and, except quantum mechanics, all the navier-stokes and fluid dynamics are solved 🤐🤫😶
if this collision thing holds true on molecular scale where quantum effects are big enough.
@kundansaurav2012 Says:
e1e2
@suhnih4076 Says:
Woe
@mzarias Says:
Tensors much?
@JustTriangle Says:
Collisions its magic)
@samsaraAI2025 Says:
Yes. And what about omegas??
@Klaus-Schwab_Dictator Says:
In explosion kinetic energy increases
@Markyparky56 Says:
Caveat: only valid for spherical chickens in a vacuum
@Leadvest Says:
The end note's assertion about angular momentum is bizarre, seems like an internal argument was left unresolved during the writing process.
@VidathWedisinghe Says:
Does dis mean dat da future is technically determined - please make a video if you contend or think it's an interesting (enough) concept! :) thanks minutephysics
@srinikethvelivela2692 Says:
This basic physics but presented with beauty !
@prosamis Says:
Correct me if I'm wrong but are the examples here just perfectly elastic?
We have the case where one of the objects become embedded in the other, which Im surprised isn't even mentioned
@ChaosSlave51 Says:
Don't rotations make this way more complicated?
@Guys-s5v Says:
how did you make those objects fall?
@HERE.AND.QUEER. Says:
Me after clapping: I seem to have done a science
@jacobcrowder2600 Says:
Bro where the hell was this video when i failed AP Physics??? 😢
@chrisg3030 Says:
1:39 "Most collisions in 2D or 3D result in a net force between the objects which is only in one direction, typically perpendicular to the surface where the objects collide". Does this account for circular impact craters (on the Moon for example) even when the collisions themselves aren't in a perpendicular direction?
@lazyken6468 Says:
Even for clapping?
@ggsap Says:
Hey Henry, the footnotes you add into the video distract from the content, how about putting them in a pinned comment?
@namanjain989 Says:
How are we supposed to derive the equations of the final velocities? I have tried, but, no, I am not trying this any more. Does somebody have a solution?
@sarmah78 Says:
Physical wallah
@shakuntalapawase3871 Says:
Can u make one video on heat equation. Like of 10th grade?
😅
@supermonkeygod Says:
We are all basically in one dimension now
@nsTurkish Says:
Turkish subtitles please
@ImplodedAtom Says:
Collisions take time though.
@НиколайБабич-ф3э Says:
your *-notices are too slow! make them faster 💪 show only during 1 frame 😈
@kongqianfu Says:
This video just taught me how to play pool
@joshuakarr-BibleMan Says:
Time.
Is it time?
@cobracoder6123 Says:
Sure, it's easy to figure out how a collision happens, but what about figuring out when they collide in the first place? For computers, that's where the complexity lies
@smolblacquecat7148 Says:
I like how the cat is unaffected by the collision in the intro >:)
@willrandship Says:
This video takes the assumptions that all physical objects can be modeled as 1 dimensional interactions, then shows the equations for those interactions and hand waves away every case where multidimensional objects aren't symmetric extensions of uniform 1D objects.
Frictionless elastic circles in 2D behave like 1D interactions because their symmetry removes any 2D behavior. The same goes for spheres in 3D. However, in real life collisions are emergent properties of multiparticle interactions, not the other way around. Nothing ever moves in a straight line, and nothing is ever uniformly symmetrical, even at the quantum level. Spacetime itself is nonsymmetric and multidimensional.
These systems of kinematics require you to dispose of more and more of the information in a system to make any of their claims hold in higher dimensions.
@Nah_Bohdi Says:
Neat!
@ziftrue Says:
Я за 4 минуты видео, понял больше чем за год в институте
@ziftrue Says:
What is Vcom??? !!!
@ThoughtinFlight Says:
Back in high school I was very weirdly obsessed with physics engines for games, can't believe how much time I spent on these equations. Thinking about them still makes me feel giddy. Then I had advanced dynamics as a post-grad, life changing most fascinating shit I ever studied. Also the most difficult.
@robb4394 Says:
I'm not smart enough for this. This is four minutes I could have been using to go through the waiver wire in fantasy football.
@Lonelykea Says:
What did you used for the collisions ?
@seanewing204 Says:
Don't like the weird gradient under the video, but I do like the new UI overall.
@AA-zo6xr Says:
Omfg if you have to add that many asterisks maybe you should just redo the video. Clearly you made a bunch of mistakes that you had to correct and now I have to pause the video every 20 seconds to see what you’re actually saying.
@ReptillianStrike Says:
This is actually the secret behind Laplase's demon.
Philosopher Laplase hypothesized that an entity that knew the location of every atom in the universe, the velocity, temperature, etc, and if that entity had enough mental power to calculate it, they would know everything that will ever happen.
@ldfinn990 Says:
question: what happens if i have a circle with a triangle shaped hole in it, and a triangle goes into the hole? there isnt a perpendicular angle, because it hits two sides.
@LordOfNothingreally Says:
Wat?
@elecbaguette Says:
I'd say it's two dimensional if you're including time, but semantics. Nice explanation!
@aspidoscelis Says:
If every collision had a bit of randomness that was a few orders of magnitude below our measurement error, would we ever know?
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