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1. ### Engineering Minimum Hamming Distance for Parity Check Matrix

That should be the minimum Hamming distance between all valid codewords, all 16 encoded strings. H (parity check matrix): 1 0 1 1 1 0 0 0 1 1 0 1 0 1 0 0 0 1 1 1 0 0 1 0 1 1 1 1 1 1 1 1 Convert H to systematic: xor first three rows to last row, creates identity matrix on right: 1 0 1 1 1 0 0...
2. ### Bias, errors, etc. within ChatGPT & other AI chatbots

One that may be fixed now: Why are cows eggs bigger than chicken eggs?
3. ### I DDWFTTW: Looking for the least confusing explanation

A simple explanation. Assume cart is moving at the same speed or slightly faster than the true wind. Use the cart's current velocity as the frame of reference. There is a newton third law pair of forces at the wheels, the earth exerts a backwards force onto the wheels, coexistent with the wheels...
4. ### Is ChatGPT just searching sites like stackexchange?

I forgot to include the a link to the 60 minutes segment on chatGPT: For example in the 60 minutes segment, chatGPT put out a fun fact that "3% of the ice in the Antarctic is penguin urine" which 60 minutes fact checked to find out it isn't true (birds don't urinate).
5. ### Is ChatGPT just searching sites like stackexchange?

A major issue is ChatGPT also collects data from unreliable sources such as social media sites. This results in incorrect responses. There was a segment on 60 minutes about this. There was also an issue that continued dialog could steer it down a dark path. Someone was able to get a ChatGPT...
6. ### I How does the mass of the wheels affect the car's acceleration?

If the wheel and tire approximate a hoop (like a bicycle tire), the affect on acceleration would be equivalent to a non-rotating object with 2.0 times the mass. If the wheel and tire approximate a solid disk, the affect on acceleration would be equivalent to a non-rotating object with 1.5 times...
7. ### I Does the aerial [antenna] not need to be positioned perpendicular?

I've seen exceptions to this. A radio control glider with the transmitter trimmed so the glider turns large radius circles, while high up. The transmitter is set down, and the "pilot" walks away for a while, returns back to find a thermal and get the glider upwind and higher, then set down the...
8. ### I Does the aerial [antenna] not need to be positioned perpendicular?

Aircraft radio control transmitters, the older 72 Mhz ones using 4 to 5 foot long antennas on transmitters, and 3 to 4 foot long antennas on the models worked regardless of orientation of transmitter or aircraft. Range was at least 1/2 mile.
9. ### Making an electric unicycle really self-balanced

Self-balancing of a human ridden electric unicycle at low speed a would require a fairly massive gyro, logic and consume power, and would interfere with ability to turn. The alternative is to use a wider tire (wider tires are more responsive to tilt), like the Ninebot Z10, which has a 4 inch...
10. ### Making an electric unicycle really self-balanced

Answering an old question - gyro effects don't play a significant role. There are two ways to steer a EUC (electric unicycle), twisting and tilting. Twisting steers directly, why tilting causes the tire to steer due to camber effect. As for stability while riding in a straight line, at...
11. ### How does a 1-wheeled motorcycle turn?

Unicycles can be steered by twisting (yaw) and|or tilting (roll). Twisting directly steers the tire, while tilting relies on camber (cone) effect to steer the tire. For any uni-track vehicle, counter-steering is used to initiate or adjust lean angle. Steer outwards to lean inwards, and once...
12. ### I Exploring the Physics of a Self-Balancing Electric Unicycle

As I posted above, similar to counter-steering, there's what I call counter-lean (forwards | backwards). Consider the case when standing on solid ground. In order to initiate a forwards lean from a vertical stance, there needs to be a forwards torque, and this is induced by pressing with the...
13. ### I Exploring the Physics of a Self-Balancing Electric Unicycle

Assume an EUC with a mass e. Assume the center of mass of the EUC is at the axle of a tire with radius r. This means leaning (tilting) the EUC does not offset the center of mass with respect to the contact patch. An inverted pendulum is directly attached to the EUC frame. The inverted pendulum...
14. ### I Exploring the Physics of a Self-Balancing Electric Unicycle

Precession may play a minor role at higher speed, but compared to camber effect, it's too small of an effect for a rider to notice any difference to tilt response. I'm not sure if precession helps or hinders camber response to tilt, depending on speed and tire parameters (the second video below...
15. ### I Exploring the Physics of a Self-Balancing Electric Unicycle

The EUC has 3 axis accelerometers and 3 axis gyros (the IMU's typically also have magnetometer, which use earth's magnetic field to determine which way is true up, but the motor field could interfere with this, and it's possible to determine which way is up|down based on feedback from...
16. ### I Exploring the Physics of a Self-Balancing Electric Unicycle

The Stanford link shows an inverted pendulum that pivots on the upper surface of cart that can only exert a linear force. In the case of an electric unicycle, the pivot point of the pendulum is offset above the point of contact with the pavement, attached to a motor that generates a Newton third...
17. ### I Exploring the Physics of a Self-Balancing Electric Unicycle

A self-balancing electric unicycle consists of a frame+pedals that the rider stands on, a motor where the stator is attached to the frame+pedals, and a rotor which is attached to the wheel+tire. An EUC is similar to an inverted pendulum: the EUC frame is free to rotate about its axis, limited...
18. ### Call program written in language B from program written in language A

Some of the libraries that involve finite field math include assembly code for carryless multiply, such as PCLMULQDQ on X86 processors. Erasure code, including cloud storage, also uses carryless multiply and|or parallel table lookup such as PSHUFB on X86, if it doesn't infringe on some patent...
19. ### Call program written in language B from program written in language A

A historical and current legacy example is Cobol programs calling assembly functions on an IBM mainframe. This was originally done because the database access functions were implemented as macros in IBM assembly, which Cobol programs would call. This in turn led to having some optimized...
20. ### I Torque required to prevent precession

The gyro in question is not affected by gravity. The frame is free to rotate about the x-axis, so how does it generate a torque about the x-axis? I recall some video where with the same or similar configuration: if rotation about y-axis is blocked, the reaction is the gyro accelerates about...
21. ### I Torque required to prevent precession

A torque is applied to a spinning gyro, and a second torque is applied to prevent precession. How to quantify the second torque? Example, a gyro spinning about the z axis is connected to a frame that can only rotate about the x axis. A torque about the x-axis is applied to the frame. What is...
22. ### Insights How Can We Jump When the Ground Does No Work?

I thought I removed that paragraph, but lost an edit. It's fixed now. I'll delete this post later, as it was just to acknowledge your post and that my prior post is now corrected.
23. ### I Musings on trampoline physics

The two main types of high end trampoline beds are string and webbed. Most string beds are "2 string" beds that use pairs of nylon strings, while webbed beds use strips of nylon. Both are very porous with very little aerodynamic drag. There are single string beds, but I don't think they are...
24. ### Insights How Can We Jump When the Ground Does No Work?

The force results in an equal in magnitude but opposite in direction change in momentum of jumper and Earth away from the center mass of Earth and jumper. Due to the Earth being massive, the change in speed of the Earth is extremely tiny, so almost all of energy goes into the jumper.
25. ### I Angular momentum and turning a bicycle

The Wiki article on counter-steering shows that during the initial counter-steer input (steer outwards to lean inwards) the estimate is that gyroscopic precession accounts for about 12 % of the total leaning torque, while most of the leaning torque, 88%, is due to outwards friction force from...
26. ### Comp Sci Troubleshooting Index Error 7 in Decoding

Are you trying to create a program or just writing out the steps as you posted in your question? Were you able to understand my encoding example? Assuming a character is a byte, then each dictionary entry = {prior index : byte}. Using my example, consider decoding d[6] onto a stack...
27. ### Comp Sci Troubleshooting Index Error 7 in Decoding

The videos don't do a good job of explaining a LZW dictionary. Link to Wiki article: https://en.wikipedia.org/wiki/Lempel–Ziv–Welch Typically elements are not stored in the dictionary. For the OP's question the elements have values 1 (A) and 2(B). To keep things simple assume that elements and...
28. ### Line Dance Swing Shim Sham at Carnation Plaza Disneyland

It's a tradition for most swing dance venues to have one Shim Sham line dance per night. My wife and I live in southern California and go to club type and swing type venues. At the club type venues, electric side and wobble are popular, partially because they are simple to learn. The longest is...
29. ### Line Dance Swing Shim Sham at Carnation Plaza Disneyland

Depends on the venue. Shim Sham is still popular at swing dance venues (or flash mobs just about anywhere).
30. ### Line Dance Swing Shim Sham at Carnation Plaza Disneyland

Achy Break Heart - 1992. Electric Slide - 1976 (first song was Electric Boogie, later other disco songs, country western songs, pop songs, ...). Van Mccoy Hustle line dance - 1975. LA Hustle (renamed Bus Stop) - 1974. The Madison - 1957. Shim Sham and Big Apple (swing line dances) date back to...
31. ### How to keep the starting time from being deleted from YouTube links?

Here at Physics FOrusm, if I post a link to a youtube video with a start time, such as ...&t=63s for a start time of 63 seconds, the conversion to a media html removes the start time. How do I fix this? Sometimes the link shows :63, but that's not working.
32. ### Line Dance Swing Shim Sham at Carnation Plaza Disneyland

Swing - Shim Sham - at Carnation Plaza at Disneyland:
33. ### I Why don't we "fly up" in an accelerating elevator?

Another example would be the vomit comet:
34. ### Assigning variable values "on the fly" within expressions

In APL, variable assignment can be done according to the order of evaluation. In this example, the right Z is declared, but uninitialized, where initialization occurs within the parenthesis. The expression is 2 modulo (Z##\leftarrow## 1 2 3 4 5) reduce Z (delete all values where Z modulo 2 are...
35. ### A Bernoulli, lift and cause & effect

I use the term coexistent to avoid a cause and effect relationship. Once the cause of downwards diversion of the relative air flow has been established (a wing at an effective angle of attack moving through the air), then pressure gradients and acceleration of air (either perpendicular to or in...
36. ### I Moving backwards with Skates

The normal method to move forwards on skates is to orient a skate slightly outwards and push outwards on a stake. The skater alternates between the two stakes to propel forwards. This is a bit more difficult to do backwards since a skater orients a skate slightly inwards and pushes outwards...
37. ### A Bernoulli, lift and cause & effect

For cause and effect, the cause is a wing with an effective angle of attack moving at some velocity through the air, and the effect is the affected air is diverted downwards (assuming level flight). A relatively simple explanation is that a wing diverts the relative air flow "downward". The air...
38. ### A question about lists in C# or Java :)

Merge sort for linked lists has time complexity O(n log(n)). For Java, you'll need to implement your own linked list, as Java's native linked list provides no equivalent of C++ std::list::splice(), which is used to move nodes within a list or from one list to another.
39. ### Comp Sci Helicopter Auto-Hover

One issue is that helicopter in steady forward flight needs to be pitched down a bit to compensate for drag. Another issue is what is the thrust to weight ratio of the helicopter, which will limit the maximum angle that can be used for acceleration | deceleration. In the case of model aerobatic...
40. ### I How a Battery creates a Potential difference in an electrical current

So what happens in a sequence where alternating poles of a battery are connected one at a time to one plate of a capacitor, with the other plate grounded, after thousands of cycles?
41. ### I How is static friction the centripetal force during a car turning?

Other than for something like a 10 speed bicycle, motorcycle tires have a reasonably large contact patch, due to a combination of tire size, profile, and soft compound rubber. The slip angle in higher g turns is significant.
42. ### I How is static friction the centripetal force during a car turning?

Via deformation. There is some actual slippage, more so during at what could be called partial contact. To answer your question though, the inside would get compressed more in the direction of rolling than the outside. The contact patch is also deformed at an outwards angle, which correlates to...
43. ### I How is static friction the centripetal force during a car turning?

Even when pure rolling, there is still significant deformation at the contact patch for typical tires. Formula 1 tires are setup with negative camber, so that involves some deformation even when going straight. As posted earlier, the hysteresis related to deformation and recovery is a...
44. ### I How is static friction the centripetal force during a car turning?

Doing a quick web search, my guess from 100 C to 130 C, but this is mentioned as the operating temperature range. Even if you knew the temperature increase, keep in mind the tires are constantly dissipating heat at a fairly rapid rate, which would also need to be taken into account.
45. ### I How is static friction the centripetal force during a car turning?

The 20 mph is the reduction in speed over a period of time from corner entry to corner exit and an extreme case (Radillion at Spa). Power is being consumed as soon as the tires deform, but the consumed power takes time to slow the car down. The worst is Spa, at Radillion, a 5 g dip (including...
46. ### I How is static friction the centripetal force during a car turning?

Getting back on the side topic of energy losses due to tire deformation, an extreme example is Formula 1 race cars, where despite being at full throttle, in high speed, high g turns, 20+mph is lost due to tire deformation. Even in medium to high speed turns, that energy goes into heating up the...
47. ### I How is static friction the centripetal force during a car turning?

or use a bit more elevator. The rudder will result in a more coordinated turn, but at higher speeds, you don't need much rudder.
48. ### I DDWFTTW: Looking for the least confusing explanation

That just shifts the divide by zero problem to some speed slightly less than wind speed, where V + delta V - W = 0.

Thanks.
50. ### I DDWFTTW: Looking for the least confusing explanation

I meant the old ones from 10 years ago. No 3d printing required, and they were lighter. Several of these were made by different people here at Physics Forums, and a parts list posted somewhere. "searching in vane" - this pun was caught a bit sooner that I thought it would be.