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this page reports that parachutists experience 33 Gs, but the citation is highly questionable and should be double-checked 74.111.225.136 ( talk) 01:31, 18 August 2014 (UTC)
This page is lacking the negative ( tiny ) acceleration orders of magnitude.
itsme (
talk) 08:53, 3 September 2015 (UTC)
Citation 2 Doesn't exist anymore. — Preceding unsigned comment added by 24.55.1.148 ( talk) 19:08, 21 September 2015 (UTC)
The table in the article uses two different frames of reference for measuring acceleration:
Before user:Cmglee's changes, the difference was hidden in the use of either g or G. Now we have the situation that the reader might compare, for example the Saab to the Bugatti and miss the reference that the Bugatti's acceleration is directed 40 deg from horizontal. This also affects the order of the table, for example the Saab accelerates faster than the Saturn V if one chooses the same frame of reference. What is good way of distinguishing the two that is easy to understand and not easily overlooked?-- Debenben ( talk) 17:56, 21 July 2016 (UTC)
@ A.R., Maproom, and Cmglee: Since there no real input or new ideas from this RfC, let me list all options that I can think of
One can also combine the options, e.g. option 3+4+5+6: create two different tables for small and large values. The table for small values using different colors and an additional row with a custom ref-tag that specifies the frame of reference. From my point of view, the worst options are (1) and (8), I just included them for completeness.-- Debenben ( talk) 16:52, 7 August 2016 (UTC)
I'd say give the accelerations as lab reference and inertial reference frame in all cases up to where it makes no difference to the number. It's a simple calculation which doesn't fall foul of WP:OR, and doesn't complicate the table with footnotes, colours or explanations, and doesn't require us to create new articles. It also means that all the cases can be simply compared with each other. We can, if you like, also give the direction of the vector, like was done with the car acceleration case, where relevant. -- Slashme ( talk) 21:31, 7 August 2016 (UTC)
The acceleration of a proton in the LHC is given in this page as 1.9x10^9 g. The formula given is (7 TeV/20min*c)/proton mass. Not sure where this comes from, but if it calculates from a zero initial velocity, then it's inaccurate. Beams go into the LHC already traveling near the speed of light (having been through other particle accelerators on the way), so they can't get much faster.
Beams enter the LHC with an energy of 450 GeV per proton. By the time they're finished accelerating, they're at 6500 GeV per proton (the energy that the collider currently operates at). Dividing energies by proton mass 0.938 GeV/c^2 gives a gamma factor of 479.7 at injection and 6,929.6 after acceleration. From equation y= 1/(sqrt(1-(v^2/c^2))), we get beam speeds of 299,791,806.5 m/s at injection and 299,792,454.9 after acceleration. The difference between these two numbers is 648.4 m/s. It takes 19 minutes to accelerate the beams all the way. From v=a*t, we find the acceleration to be only 0.55 m/s^2 (0.056 g).
Treating the LHC like a centrifuge, however, is how we get all the Gs. Centripetal force = (mv^2)/r. Force also = m*a. So m*a = (mv^2)/r. Since the beams are going so fast, we need to take relativity into account. So we multiply (mv^2)/r by the gamma factor, which is 6,929.6 at full energy. The beams are bent around a radius of 2,803 m. Working with m*a = (y*mv^2)/r, we get centripetal acceleration of 2.22x10^17 m/s^2 (2.27x10^16 g). This is much greater than the acceleration figure given on this page.
Savie Kumara ( meow) 06:48, 13 August 2016 (UTC) Savie Kumara ( meow) 06:48, 13 August 2016 (UTC)
Correction: the page states LHC proton acceleration as 1.9x10^8, not 1.9x10^9. Savie Kumara ( meow) 07:02, 13 August 2016 (UTC)
This link gives many parameters of the LHC, including numbers I used (energy & gamma factor at injection and the collider's bending radius). https://edms.cern.ch/ui/file/445830/5/Vol_1_Chapter_2.pdf Savie Kumara ( meow) 07:16, 13 August 2016 (UTC)
The acceleration values in the table are average value, considering the ratio between the total change of speed (100 km/h) and the duration of the change. It would be more interesting to know the maximum acceleration: no car has a constant acceleration: the torque vs. rpm curve of the motor, the change of the gear rapport (if not an electric car) and the aerodynamical friction make the acceleration higher at the beginning and lower at the end. As I said, it would be more interesting to know the maximum acceleration: I suppose that the most of the other values are the peak value and not the average. -- Angelo Mascaro ( talk) 20:38, 26 January 2017 (UTC)
The cite for the acceleration of a jellyfish stinger does not provide details on the claim for the high acceleration. It mentions a response time and velocity, but not a travel time or distance for the stinger that achieves a modest speed of 18.6 m/sec. Equating the response time from the cite with the travel time of the stinger, the apparent constant-acceleration is (18.6 m/s) / (700 e-9 s) = (26,571,428 m/s^2) / (9.8 m/s^2) = 2,711,370-g , not 5.4e6 g. The cite doesn't say how a higher-than-constant acceleration of the stinger was determined -- if the response time and the travel time are the same. The Wikipedia article on jellyfish does not mention the acceleration of the stinger. - 71.166.96.134 ( talk) 04:08, 18 June 2018 (UTC)
This article is rated List-class on Wikipedia's
content assessment scale. It is of interest to the following WikiProjects: | |||||||||||
|
this page reports that parachutists experience 33 Gs, but the citation is highly questionable and should be double-checked 74.111.225.136 ( talk) 01:31, 18 August 2014 (UTC)
This page is lacking the negative ( tiny ) acceleration orders of magnitude.
itsme (
talk) 08:53, 3 September 2015 (UTC)
Citation 2 Doesn't exist anymore. — Preceding unsigned comment added by 24.55.1.148 ( talk) 19:08, 21 September 2015 (UTC)
The table in the article uses two different frames of reference for measuring acceleration:
Before user:Cmglee's changes, the difference was hidden in the use of either g or G. Now we have the situation that the reader might compare, for example the Saab to the Bugatti and miss the reference that the Bugatti's acceleration is directed 40 deg from horizontal. This also affects the order of the table, for example the Saab accelerates faster than the Saturn V if one chooses the same frame of reference. What is good way of distinguishing the two that is easy to understand and not easily overlooked?-- Debenben ( talk) 17:56, 21 July 2016 (UTC)
@ A.R., Maproom, and Cmglee: Since there no real input or new ideas from this RfC, let me list all options that I can think of
One can also combine the options, e.g. option 3+4+5+6: create two different tables for small and large values. The table for small values using different colors and an additional row with a custom ref-tag that specifies the frame of reference. From my point of view, the worst options are (1) and (8), I just included them for completeness.-- Debenben ( talk) 16:52, 7 August 2016 (UTC)
I'd say give the accelerations as lab reference and inertial reference frame in all cases up to where it makes no difference to the number. It's a simple calculation which doesn't fall foul of WP:OR, and doesn't complicate the table with footnotes, colours or explanations, and doesn't require us to create new articles. It also means that all the cases can be simply compared with each other. We can, if you like, also give the direction of the vector, like was done with the car acceleration case, where relevant. -- Slashme ( talk) 21:31, 7 August 2016 (UTC)
The acceleration of a proton in the LHC is given in this page as 1.9x10^9 g. The formula given is (7 TeV/20min*c)/proton mass. Not sure where this comes from, but if it calculates from a zero initial velocity, then it's inaccurate. Beams go into the LHC already traveling near the speed of light (having been through other particle accelerators on the way), so they can't get much faster.
Beams enter the LHC with an energy of 450 GeV per proton. By the time they're finished accelerating, they're at 6500 GeV per proton (the energy that the collider currently operates at). Dividing energies by proton mass 0.938 GeV/c^2 gives a gamma factor of 479.7 at injection and 6,929.6 after acceleration. From equation y= 1/(sqrt(1-(v^2/c^2))), we get beam speeds of 299,791,806.5 m/s at injection and 299,792,454.9 after acceleration. The difference between these two numbers is 648.4 m/s. It takes 19 minutes to accelerate the beams all the way. From v=a*t, we find the acceleration to be only 0.55 m/s^2 (0.056 g).
Treating the LHC like a centrifuge, however, is how we get all the Gs. Centripetal force = (mv^2)/r. Force also = m*a. So m*a = (mv^2)/r. Since the beams are going so fast, we need to take relativity into account. So we multiply (mv^2)/r by the gamma factor, which is 6,929.6 at full energy. The beams are bent around a radius of 2,803 m. Working with m*a = (y*mv^2)/r, we get centripetal acceleration of 2.22x10^17 m/s^2 (2.27x10^16 g). This is much greater than the acceleration figure given on this page.
Savie Kumara ( meow) 06:48, 13 August 2016 (UTC) Savie Kumara ( meow) 06:48, 13 August 2016 (UTC)
Correction: the page states LHC proton acceleration as 1.9x10^8, not 1.9x10^9. Savie Kumara ( meow) 07:02, 13 August 2016 (UTC)
This link gives many parameters of the LHC, including numbers I used (energy & gamma factor at injection and the collider's bending radius). https://edms.cern.ch/ui/file/445830/5/Vol_1_Chapter_2.pdf Savie Kumara ( meow) 07:16, 13 August 2016 (UTC)
The acceleration values in the table are average value, considering the ratio between the total change of speed (100 km/h) and the duration of the change. It would be more interesting to know the maximum acceleration: no car has a constant acceleration: the torque vs. rpm curve of the motor, the change of the gear rapport (if not an electric car) and the aerodynamical friction make the acceleration higher at the beginning and lower at the end. As I said, it would be more interesting to know the maximum acceleration: I suppose that the most of the other values are the peak value and not the average. -- Angelo Mascaro ( talk) 20:38, 26 January 2017 (UTC)
The cite for the acceleration of a jellyfish stinger does not provide details on the claim for the high acceleration. It mentions a response time and velocity, but not a travel time or distance for the stinger that achieves a modest speed of 18.6 m/sec. Equating the response time from the cite with the travel time of the stinger, the apparent constant-acceleration is (18.6 m/s) / (700 e-9 s) = (26,571,428 m/s^2) / (9.8 m/s^2) = 2,711,370-g , not 5.4e6 g. The cite doesn't say how a higher-than-constant acceleration of the stinger was determined -- if the response time and the travel time are the same. The Wikipedia article on jellyfish does not mention the acceleration of the stinger. - 71.166.96.134 ( talk) 04:08, 18 June 2018 (UTC)