This channel is dedicated to taking an in-depth look at all things physics in a rigorous yet spirited manner. The main goal is to break down a complex phenomenon into bite-sized chunks so that the entire phenomenon can be understood as a series of interconnected, easy-to-understand pieces. And while I do not shy away from using mathematics, I try to approach things so the math is not required for understanding the essence of the phenomenon. Leave a comment if there are specific things you would like to see discussed; no promises, but I'll try.
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Who thought c was wrong?
stop making people crazy with simple things first let's calculator the weight of spring & ball. ounce the spring is off the line it's weight is on other direction than we notes a change
string doesn't have a weight it's different & it can balance because of it's weight. by test these two you shall see the difference between
When an exam like question is presented, it is always presumed that all conditions are ideal unless otherwise stated. Had you stated the non-ideal nature of "the string", the answer would have been obvious. Consider integral calculus. As the propagation speed along the string increases, the arc-time of the ball decreases. In other words, as the string propagation time aproaches zero, the arc-length also approaches zero. Thus, the ball is moving tangentially at any instant in time. The only time the ball will move along the original arc is when that ball is held in place by a radial force. But that was not implied in your original statement of conditions. "When I shit, does my crap fall straight down?" The answer might surprise you! 😅
Beatiful video
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I bet one use the deviation from tangent to calculate the speed of that tension wave. Great video!!
Indeed! Good point!
Nope nope, I refuse to accept this scientific fact.... I thought b is right, and so shall it be or I'll get emotional damaged, depressed and ill start doing drugs.
The earth continuing to orbit correctly implies that the expansion/contraction of space-time is the “weightless” string that holds us in orbit. When the sun vanishes, space-time re-expansion propagates outward from the now unwarped center. Just as the pre-existing tension in the slinky holds the ball in place until the decompression wave arrives. There is pre-existing gravitational tension between things because they are things. Chew that a bit, then rinse and spit.
For the ball attached to one end of a slinky , a noodle , and a string , as well as for the sun vanishing , in each of those cases it will take a while for the “ news “ of the event of the release or of the sun vanishing to reach the other end . Similarly for a slinky being dropped vertically - but in that case , it really is astonishing how the bottom end remains suspended in space for a measurable few moments ! Never saw or even thought about that before ! Now I’m gonna hafta go and buy one of those slinkys and see this up close for myself !!!
Good luck…the slinky happens very fast so you’ll have to watch carefully!
I have to say it again. WOW. 😮 Thank you 😊
Ha ha…thanks again! And I do have new content in progress…so stay tuned!!
Unbelievable. 😮 Thank you so much. 😊
Thank you for the kind words!!
It is a great video, sub for you and greetings from Poland. It seems for me that TENSION in the string do similar job as gravitational force in 4dim spacetime, am I right? :) It is mindblowing!
Thanks! And yes, I agree that it’s mind blowing!!
A "path" followed in an "immediate moment" is a concept that I can not make sense of.
BULLSH** this demo/lecture disregards several basic engineering and dynamics principals. Back to school for the narrator...
Please repeat experiment with a microchip to a trigger attached to the ball. Then the slink. The moment you release the slink on one end let the chip release the slink on the ball end. I bet the ball will fly into path B while slink lingers on for the wave and eventually follow suit.
The reality is that it follows path B. The reason why it continues to follow path A is that effect cannot supersede causality. In other words if the information of release is not arrived to the ball what effect can that have in the ball. Your experiment is best to demonstrate that information does indeed have a mass. It get converted into effect the moment it arrives on intended recipient.
Come to think of it 8 months later, another thing has been left out and it should be mentioned. We are not mentioning the start of the experiment. The ball did not all of a sudden start moving in circular motion. It took some doing for the ball to get to the position of its orbital path, by means of the spring, string or whatever. The ball did not quantum jump from the center of rotation to the position of the orbit. There was a time delay, some doing to get it to move out to where it begins to move in the orbit. So, it takes time at the end for the ball to know that it is released just the same.
Highöy misleading borderline clickbait.
Bravo! Oddly enough, the final example of a disappearing sun sent the bolt home for me. Once you see that as long as the object experiences a force in the direction of the center of rotation, it will continue to rotate, the whole thing comes together. It would have been interesting to contrast this case with that of something rotating by virtue of a force not exerted from the center, but from the outside: a marble spinning within a hoop of some sort. Remove the loop and the marble will zoom out in a straight line immediately, since the force on the marble is lost instantaneously. @pataplan's comment makes the same point as this, I now see.)
There are so many amazing things we find when we look at how physics really plays out over what we think.
Great... I liked it..❤❤
Thank you! Cheers!
Why not release at the point where the string connects to the ball?
Superb video.
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The ball should have been released from the ball not at the center with the string attached. The rotation of the string and the tension wave caused the tangent trajectory to be perturbed.
This is fantastic, but yeah I think it’s a bit of a bait and switch. Not quite, but I think the tendency is to consider the ball as a single entity, when in fact the presentation is in fact a ball and string being released. Well presented and explained, except the initial presentation leads (me at least) into a set of incorrect assumptions. Once presented with the slinky, it seems obvious.
Vrlo kvalitetno objašnjeno.Ja sam nešto slično pokušavao pokazati sa sekirom ali nisam imao dovoljno kvalitetnu kameru da to i dokažem.Pa su me ismijavali. Ja sam naime tvrdio da ima tu nešto više od običnog udaranja i da se maksimalni efekt postiže jednom petljom a ne pravocrtnim kretanjem sekire prema drvetu.Hvala za ovaj kvalitetni video.Pozdrav iz Hrvatske.
I got really confused right now If i make the slinky go around in a complex pattern instead of just a circle idk, something like x = t^3-t and y = t^5-sin(t) and i release it just like in the video, will its tip keep following the same curve for a couple of miliseconds and then stop? This seems insane, these curves are so complex there's no way the slinky would know what they will look like a couple of seconds in the future. Maybe the tip just follows the taylor serie's second degree approximation after the slinky is cut ( that seems to make more sense than the tip guessing what the curve will look like ) but i would really like if someone cleared this up for me
If my guess is right and the tip just follows a second degree taylor series approximation then in fact if we got a longer slinky ans repeated the video experiment, we'd see the tip follow a parabolic path eventually, deviating from the circular one
I think you are correct, actually. Whatever motion you have made with one end of the slinky will be "remembered" for a short time in the coils of the slinky itself. For example, suppose you were holding a slinky with your hand and moving the top end up and down. This motion would cause the coils of the slinky to change with time and would, after a time delay, result in the bottom tip of the slinky to also moving up and down. The key point is that the motion of the top will be embedded in the coils of the slinky and these forces will continue to propagate down the slinky and affect the bottom of the slinky. So, in theory a complicated motion at the top will still get transferred to the bottom, resulting in a complicated motion at the bottom! That's super cool! I hadn't thought about that before!
@@AllThingsPhysicsKZread I thank you for replying and believe your idea of "remembering" carries some great insight, but i think there's still a conundrum, i'll try to be precise ( sorry for being overly long ): First of all is the observation that, if i draw to you only part of a curve there's obviously an infinitude of ways to continue it. Second is the remark that, as you have beautifully shown in the video, the tip of the slinky, after that top part is cut, seems to follow it's path for some time as if the top part hadn't been cut but had continue following the curve it was going through ( this is where the conundrum lies ). Let's suppose we make the tip of the slinky follow a curve x1(t), y1(t) and x2(t),y2(t) where these curves are defines for all t >=0. Let's now make x1,y1 and x2,y2 be respectively equal to each other for all t <= t_c ( so x1,y1 and x2,y2 are the same curves for t <= t_c but after it, they diverge from each other ). Now obviously if we make the top of the slinky follow the curve x1,y1 it will make its tipo follow some other curve X1, Y1 and the same for x2,y2 and X2,Y2. So X1,Y1 represents the curve the tip of the slinky would follow if its top followed x1,y1 and the same for 2. But now, let's suppose we make the top of the slinky follow x1,y1 untill we cut it at t_c, since both x1,y1 and x2,y2 are equal for t<=t_c, the question is which path will it follow momentarily after being cut: X1,Y1 or X2,Y2? Put in simpler words, the tip of the slinky, after the top is cut, follows the path it'd have traveled if the top had continued through the curve it was going through but the thing is, there's a multitude of curves it could have been going through ( by observation 1) so which is the one the tip considers?
@@victormd1100 I believe the paths x1,y1 and X1,Y1 are causally connected. So if the top follows x1,y1, then the tip will follow X1,Y1, but delayed due to the speed of the tension wave. In other words, the motion of the top before being released, call it x1,y1, is causally related to the motion of the tip X1,Y1. Whatever the top "would have" done after t_c is immaterial because this information is not "embedded" in the coils of the slinky at t_c. It is only the information contained in the coils of the slinky at time t_c that will have an effect on the tip of the slinky, and this information comes from x1,y1. I hope that is clear.
Di you consider the fact that the center wobbles?
Both ways are correct
Fun video. I admit I fell for it and was upset with your answer until I followed your logic. Very nicely done and entertaining. Thanks!
Thanks!!
Check out the antikithera mechanism AKA flat earth working model
cut the slinky at the ball then show the results
F=mA is what makes the ball to follow circular trajectory after tethering . Is this correct?
Yep. The tension force continues acting for a short time after the string is released.
Given that the ball is not being swung by an infinitely rigid rod/object, it will take a “while” for the ball to realize that the string has been let go of.. so it does follow that the instantaneous direction of the motion of the ball right after the string is cut/released will still be along the circle… fascinating video, lovely to see the slinky experiment
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For years I have demoed and taught answer 'b' to my students, that the ball flies off tangentially to the circular path. This is because we premise our understanding of the problem as the ball experiencing some inward tension, and then none at all. In most of this video however, tethers with varying spring force are demonstrated so the ball maintains a circular path for a brief time because the tether continues to exert an inward tension on the ball. This is not classically how the problem is defined however so it's a little disingenuous to say or imply that most physicists get this wrong.
No, this is not classically how the problem is typically posed or thought about, but that’s what makes it fun and interesting!
@@AllThingsPhysicsKZread Fair enough. It was indeed insightful and quite intriguing to see the ball continue along a circular path, even if briefly, using various tethers. Kudos to your team for their setups and videography for capturing such detail that would be beyond the reach of most.
@@ProfessorV. It was a lot of fun, but also a lot of work. Hopefully, now that classes are done I will be able to put together a few more videos. I've got a long list of really interesting things to pursue!
Does the mass of the centrifuge, however small, have any effect on the result ?
Sick dye bruh🫠
I have done THIS EXPERIMENT at 1:40 THE ANSWER IS 👉🏻👉🏻B At 2:50 this is a NON -INERTIAL observation--THEREFORE - FALSE !
Tell that to David, he rotates the stone and when released it goes directly to Goliath.
The final cop out that "release of the ball from the connection gets the tangent curve expected" - was just tacky.🙄 A very pure experimental test of this case is totally possible and should be included.
I love the text animation how did you make it 😊
I use a program called manim (a Mathematical ANIMation engine), written by Grant Sanderson of @3Blue1Brown. If you're interested, I give a shoutout to Grant in this video: kzread.info/dash/bejne/n6VrzJeje9u8XZM.html. Enjoy!
If you answer the same question with no reprising strings or springs. Take a steel ball with a non elastic string of the least weight. Then...every body with basic fisics will know the correct answer. (B)
Part of the point of the video is to make people realize that there are no “ non elastic” strings…not even a steel string!
Everyone loves a slinky.
Actually, a fourth option, curving away outward from the straight line option should be included. This is the one most people choose. I've never seen a student choose continuing in a circle or turning abruptly 90⁰ straight outwards.
An object in motion continues along that motion until acted upon an by an outside force. Pretty simple, but you can make it hard as you want.
Could you explain how friction causes a wheel to begin rolling forward?
If there were zero friction, then the wheel would be totally unaffected by any horizontal forces from the ground. Thus, if it was not spinning at all, it would remain "not spinning" while sliding along the ground (think of really slippery ice). But if there is friction with the ground, then the ground will impart a horizontal force acting at the point of the wheel in contact with the ground, and this force will cause a torque about the center of mass, which will lead to an angular acceleration about the center of mass. The result is that the wheel's rotational velocity will change. If it is not rotating initially it will begin to rotate due to the friction force from the ground. Hope that helps!
@@AllThingsPhysicsKZread Thank you for your reply! I would like to know how friction makes a wheel roll forward or backward instead of just spinning in place. I understand that friction provides the force to make the wheel roll, but I'm unsure about the specifics of how this happens. I have an explanation, but I'm not sure if it is correct. Could you please take a look at it? Here is the link: kzread.infolxwDwGvLbP0?feature=share (KZread will delete my comment if I it has external links, so I change the picture to a video, and put text in the comment).
@@cosmosben6726 The mechanism of how a spinning wheel becomes a rolling wheel is discussed in detail in this video: kzread.info/dash/bejne/k6l-steze8zNd6Q.htmlsi=n-2dwlVCTXjbzvB7.
And b
i hate questions like these. i usually get beaten up for assuming things (i really do). this question just puts you in the spotlight so that everyone sees you slippin when you assume stuff. all because someone decided to intentionally not say important details. imagine getting asked this on an exam. and you arent even in a high school yet. what are you supposed to say? why do i have to read examinator's mind? what if its in a test and you cant ask questions? thats just foul play. the right answer is to say screw yall and move on. this is really a pemdas question to ask someone so that you can say "haha youre wrong im smart"
Perhaps you could just appreciate the fact that this is NOT a test and enjoy the process of learning something new and interesting. But it’s up to you how you choose to respond.
@@AllThingsPhysicsKZread you are right
Առանց ֆոկուսների լցվեք էջս,թեմաներդ' թարգմանած բերեք,պատասխանները ստացեք,ծախեք,ժլատ չեմ,ՀԱՑ եմ,յաշիկ մաշիկ,նայած որիդ էնչ է պետք։Բայց հիշեք,արդար մազը' չի կտրվում,հարամ գերանը' էն կոտրվելն է կոտրվում,որ աշխարհն է զարմանում,ես մկներին ծակերից հանելու համար եմ կշտացնում,ըհն,ձեռի հետ երկու աֆորիզմ,չհաշված' մնացածը,թե' հասկանաս,հեղինակիր,ուրախացիր😅+**12
the ball would always move in circular motion for a brief moment in time even theoretically as the tension wave even in a massless string can not travel faster than the speed of light ergo the ball is very briefly in circular motion both in theory and practice