Added: 1 year ago
From: NatSciDemos
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  • God I love science and waiting when religion can be scientifically proved

  • it doesn't fall faster, the cup just falls shorter due to placement on the plank. try holding a finger tip under the ball, yes it falls straight down the cup moves because it sits on the plank

  • both of them fell slower than g. to actually reach the speed of g you must set the experiment in vacuum environment and to get faster than g you have to take to Jupiter or Sun or any other Cosmical object heavier than Earth

  • they are falling at the same speed it is just the marble is higher and you put the cup under it

  • the ball is centimeters up the cup, so it haves to travel more distance

  • The ball remains a constant height above the cup, and the ball falls in a straight line. The vertical component of the cup's velocity of is therefore same as the ball's vertical velocity. Gravity at sea level is a vertical force. Therefore no object here is falling faster than g, it is just an optical illusion

  • The bearing (the ball) is the one thing we trust to move at its predicted rate. The center of mass of the beam falls at ALMOST g, but some of the work is transferred into rotation rather than downward movement, because the left end is hinged.The right end not only falls with the center of mass, but rotates clockwise around it. Yes, the cup moves downward faster than gravity pulls it. But only part of that is "falling". The rest is rotation.

  • So what? And whats "g"?

  • @daimonionen g is an object's weight divided by its mass.

  • @daimonionen

    G is the acceleration of an object due to gravity

  • Awh man so cool where do you get all these ideas? :)

  • I don't understand why you would think the cup is falling faster than g? It's not. The ball starts higher than the cup, that's why the ball can make it INTO the cup. It's not defying the laws of physics or breaking theories in any way shape or form.

  • @psiewert83 It is indeed falling faster than g and it still isn't breaking any laws of physics. The fact that the bearing moves off the stick is proof of that.

    The center of gravity of the board will (almost) always fall at g. If it was released from some height without the pinned end, the board, cup, and bearing would all fall at the same rate with no rotation (ignoring air resistance). However, since the end is pinned, it causes the board to rotate... (more)

  • @psiewert83 and because the center of gravity of the board is between the hinge and the free end, the latter falls faster than g.

    I hope that made sense.

  • How large would you have to scale up this demonstration to show the effect the motion of the earth has on the free falling steel ball? Can it be done?

  • @gwg68 By VERY CAREFULLY releasing the ball in a controlled manner, you can measure its (very small) deflection when it's dropped from a height of three or four stories.

  • people are too nitpicky. these videos are great, and i am watching as many as i came. i definitely subscribed. thanks!

  • Very fun! You can look at the steel ball with a vertical reference to check that it falls vertically! I also checked that the ball starts without no upward initial velocity with an horizontal line... I' m going to look at it with pymecavideo! I can get a scale assuming that steel balls aceleration is about 9,8 m/s^2...

  • Also, it would be nice to have a scale in the background, which would allow a frame-by-frame speed determination, as well as showing clearly what vertical distance is between the ball and cup both at the beginning and at the moment that the cup hits the table. Great, now I've got to get access to a high-speed camera so I can do this demonstration myself!

  • @Chasmodius yes a grid would help and we would have used one if we weren't so lazy. as you can see from the high speed footage the lens adds a bit of distortion, so the challenge would be to overcome that. if you do make your own (and we encourage you to) we found that a yogurt cup works well ;)

  • I think the title is misleading: while the end of the board (and therefore the attached cup) are ACCELERATING faster than ~9.8 m/ss, it's hard to tell that it is "falling" (that is, the component of the acceleration that is directly downward is) faster than ~9.8 m/ss. This is stated more accurately in the description, but I think the use of "falling" is confusing in the title. That said, this is still a really interesting demonstration about some of the oddities of physics.

  • @Chasmodius yes the name of this demo is intentionally misleading so that the class can have a discussion of what is really happening. thanks for watching!

  • The board isn't falling at a faster rate the g. The cup is always lower then the ball. What happens is that as the board moves around the hinge it changes the position of the cup to bellow the ball. So since the rate is the same for both objects and the ball started higher up from the floor then the cup, the cup lands first then the ball falls in it.

  • @bskrtich Nope, look at the end of the board. It definitely shows the point moving vertically further away from the ball as it descends. AND it had to travel a greater distance.

  • So, the center of mass of the board accelerates at G, and one end slower, and one end faster? Like if you spun a bike tire off a roof, one side would be traveling downwards faster than the other, but the tire as a whole would accelerate at G?

  • @NatSciDemos Love the videos. Wish you guys were at my Uni, would have been way more fun :) Thanks for sharing!

  • Isn't it just natural air resistance? The plane of the board cuts through the air, while the ball meets resistance under it's curved base.  The ball falls straight down a touch slower.

    What if you put this device in a vacuum?

  • @leftovcenta true, drag has some effect on the system, but not a lot--the solid steel ball bearing is quite dense and is affected very little by air resistance. in vacuum the ball would still land in the cup. see the writeup linked from the video description for more explanation, and thanks for watching!

  • That was awesome.

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