Timeline for The falling broom handle
Current License: CC BY-SA 4.0
35 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| S Oct 25, 2019 at 9:27 | history | bounty ended | Conifers | ||
| S Oct 25, 2019 at 9:27 | history | notice removed | Conifers | ||
| S Oct 24, 2019 at 8:10 | history | bounty started | Conifers | ||
| S Oct 24, 2019 at 8:10 | history | notice added | Conifers | Reward existing answer | |
| Oct 24, 2019 at 1:44 | answer | added | user235510 | timeline score: 1 | |
| Oct 23, 2019 at 13:40 | comment | added | Weather Vane | @WooShell that is what happens in the linked example posted by Conifers: the ball lands in a cup fixed to the beam. | |
| Oct 23, 2019 at 13:14 | comment | added | WooShell | D) The key hits the broom handle | |
| Oct 23, 2019 at 11:48 | comment | added | Zizy Archer | This is somewhat similar to a challenge "lie down faster than ball drops (from height of your head at the same time)". | |
| Oct 23, 2019 at 8:12 | comment | added | Conifers | @JaapScherphuis Yes, but the cut-off angle is so common that could be the implicit premise for this puzzle...?(At least I don't know after the xnor's proof... :( ). Anyway this puzzle is good for the counter-intuitive clarification and fun in reality :) I may personally give xnor a bounty due to let me take a physic class :P | |
| Oct 23, 2019 at 7:45 | comment | added | Jaap Scherphuis | @Conifers But it isn't. That's reality for you. When I posed the question I knew the cut-off angle was somewhere in the 40s or 50s and set it up to be comfortably below that. | |
| Oct 23, 2019 at 7:33 | comment | added | Conifers | @JaapScherphuis Yes the 2.69ft broom may be unusual, but if the cut-off angle is proven only 10 or 20?... | |
| Oct 23, 2019 at 7:26 | comment | added | Jaap Scherphuis | @Conifers have you ever seen a broom that is $\frac{2\text{ ft}}{\sin 47.9}=2.7\text{ ft}$ or shorter in length? | |
| Oct 23, 2019 at 7:21 | comment | added | Conifers | @JaapScherphuis I agree that this puzzle is the big picture, not to detailed calculated the specific figures, however proven by xnor, neither 3 options are the best correct answer due to angle is undefined. Although you mentioned the off-ground height, but the broom length is unknown. I don't quite agree that broom should exist the common length to let you guaranteed the angle is always less than 47.9 proven by xnor. | |
| Oct 23, 2019 at 6:38 | comment | added | Jaap Scherphuis | @Conifers I did not intend for this to be a calculus problem. I asked for what happens and the reason why, and the answer I accepted was the first to explain the counterintuitive result. While one could calculate the effects of rotational inertia, the effect of the lateral movement due to the friction with the ground, and throw in friction with the air as well while you're at it, the fact remains that the effect of these is small enough to not change the answer in the situation as described and pictured in the question. The question is intended to be about the big picture, not the details. | |
| Oct 23, 2019 at 4:53 | answer | added | xnor | timeline score: 39 | |
| Oct 23, 2019 at 4:40 | comment | added | Conifers | @PiIsNot3 For(2) compared to your thoughts, this puzzle involved more specific physic property like Angular Momentum or Torque, which you will be learned in high school or university, should not so common...(maybe to think if this puzzle need calculus to solve, then it should belong to the PuzzleSE or MathSE? ) | |
| Oct 23, 2019 at 3:04 | comment | added | HTM | @Conifers For (2), see here for my thoughts. As for (1), that could be remedied by providing additional specifications, such as what the OP did in a comment above | |
| Oct 23, 2019 at 1:36 | comment | added | Conifers | I tend to give this puzzle may not belongs here due to: 1) Insufficient criteria to solve this question by unknown angle of the broom. 2) If the angle could be calculated by the image shown(maybe you are measuring on your screen :D), then this puzzle should belongs to Physic Exchange due to involve specific physic formula/property to solve it. | |
| Oct 22, 2019 at 23:15 | review | Close votes | |||
| Oct 23, 2019 at 8:10 | |||||
| Oct 22, 2019 at 22:59 | comment | added | xnor | Beyond not specifying the mass distribution and initial angle, it's not clear whether we assume there's a) no friction between the broom end and the ground, in which case it slides freely; b) total friction, in which case the end stays fixed like a hinge; or c) something in between. | |
| Oct 22, 2019 at 20:26 | answer | added | Merlin3189 | timeline score: -1 | |
| Oct 22, 2019 at 18:27 | comment | added | Weather Vane | Yes, the picture does show a broom angle of around 20°, rather less than the critical angle 35.3° given in the link from Conifers. I would say the effect of the broom head, being relatively massive, would be to make it a "hinged" rod and otherwise of no consequence. | |
| Oct 22, 2019 at 18:22 | comment | added | Jaap Scherphuis | @WeatherVane In the question I say the end is two feet off the ground, and with a normal sized broom of about 5 feet you get an angle just below 25 degrees, very similar to what the picture in the question depicts. Broom handles almost always have a uniform mass distribution, and just like nearly every physics problem it is perfectly reasonable to assume uniform density without having to explicitly state so in the question. The mass of the head of the broom has virtually no effect since it is on the ground already. | |
| Oct 22, 2019 at 17:31 | comment | added | Jeffrey | You accepted a wrong answer. In fact, the problem is ill-defined, and depends on the mass distribution and angle. | |
| Oct 22, 2019 at 17:16 | answer | added | AndH | timeline score: 2 | |
| Oct 22, 2019 at 16:33 | comment | added | Weather Vane | As the starting angle of the broom has not been stated, there would appear to be more than one correct answer, or, the answers given are incomplete. | |
| Oct 22, 2019 at 16:25 | comment | added | Guntram Blohm | Imho this should be migrated to the physics site for a definite answer. | |
| Oct 22, 2019 at 13:54 | history | became hot network question | |||
| Oct 22, 2019 at 13:53 | vote | accept | Jaap Scherphuis | ||
| Oct 22, 2019 at 10:42 | comment | added | Jaap Scherphuis | @OmegaKrypton I guess so. I added the Real tag. | |
| Oct 22, 2019 at 10:41 | history | edited | Jaap Scherphuis |
edited tags
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| Oct 22, 2019 at 10:29 | comment | added | Omega Krypton | real tag as well? | |
| Oct 22, 2019 at 10:17 | answer | added | AndyT | timeline score: 18 | |
| Oct 22, 2019 at 8:05 | answer | added | Weather Vane | timeline score: 9 | |
| Oct 22, 2019 at 5:48 | history | asked | Jaap Scherphuis | CC BY-SA 4.0 |