Talk: Acceleration

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Pna (partial listing)[]

Includes the verb forms accelerated, accelerates, accelerating
Related terms: rate of acceleration, acceleration curve, acceleration delay

Speed or Velocity

TOS

TAS

TAS: "Beyond the Farthest Star"
TAS: "The Time Trap"

TOS films

TNG

TNG films

DS9

VOY

ENT

DIS

DIS: "Si Vis Pacem, Para Bellum"

Biology

May need its own page

TOS

TOS: "Wink of an Eye"

TAS

TAS: "The Terratin Incident"

TOS films

TNG

TNG films

DS9

VOY

ENT

DIS

DIS: "The Wolf Inside"

--Memphis77 (talk) 22:43, August 9, 2020 (UTC)

Definition[]

In this article, the definition,

"Acceleration was an increase in speed or velocity. TOS: "The Galileo Seven""

is not entirely correct. As a scalar quantity, acceleration is the rate of change of speed with respect to time.

As a vector quantity, acceleration is the rate of change of velocity with respect to time.

Change of speed is not equivalent to change of velocity. The reason is that speed is not equivalant to velocity. Speed is a scalar quantity, which in the case of speed, is the magnitude of velocity.

On the other hand, velocity is a vector quantity, a quantity that has both magnitude (that is, speed in the case of velocity) and direction.

So, change of velocity can involve either change of speed without change of direction, change of direction without change of speed, or a change of both speed and direction. An example of change of direction without change of speed is a satellite orbiting a planet at a constant speed, but because its velocity constantly changes direction, the satellite still experiences an acceleration (more specifically, acceleration due to a centripetal force, the gravitation of the planet).

Additionally, depending on the direction of acceleration of a body relative to the direction of velocity of the body, acceleration can result in either an increase or a decrease in speed or velocity. For instance, if a motor vehicle, traveling on a east-west highway at a speed of 100 kilometers per hour in the westward direction, is braked, the vehicle will experience acceleration in the eastward direction (the direction opposite the velocity's direction), such that the speed decreases. That is, the vehicle will experience deceleration.

In the definition, the citation of the episode TOS: "The Galileo Seven" is not valid. In this episode, acceleration was never defined. Neither was it ever mentioned in the context of either speed or velocity:

Just after the Shuttlecraft Galileo was launched from the Enterprise (NCC-1701), Mears reported to her crewmates on the Galileo, "Readings normal. Acceleration normal. Phase one separation normal."

And conversely, neither speed nor velocity was ever mentioned in the context of acceleration:

When McCoy, after asking his crewmates on the shuttlecraft if they were all right after they were grounded on Taurus II, asked what happened to them, Boma provided an evaluation, "I can't be sure, but I'd say that, the magnetic potential of the effect was - (McCoy gives him a tissue for his nose bleed) Thank you - was such that, as we gathered speed, it was multiplied geometrically. And we were simply shot into the center of the effect. Like a projectile."

After Scott declared that the damage to the Galileo was very bad and Spock asked in what way, Scott replied, "We've lost a great deal of fuel. We have no chance at all to reach escape velocity. And if we ever hope to make orbit, we'll have to lighten our load by at least five hundred pounds."

After abandoning the search for the shuttlecraft, Kirk ordered, "Mister Sulu, proceed on course for Makus III, at space normal speed."

And after surmising that the thing that Sulu discovered was holding a steady lateral line at Taurus II was the Galileo in orbit of that planet, Kirk commanded, "A hundred and eighty degrees about, Mister Sulu. Lieutenant Uhura, contact transporter room. All beams ready. Full normal speed."

I have therefore corrected the definition in this article and deleted the citation.

-- Astrophysicophile (talk) 08:54, 25 March 2024 (UTC)

Measurements[]

In the article, the measurements for acceleration are not correct. The example units provided, kilometers per second and kilometers per hour, are actually units for speed or (magnitude of) velocity.

By dimensional analysis, the units of measurement for (magnitude of) acceleration are:

[distance] per [time]²

or

[distance] per [time] per [time]

An example is:

kilometers per second²

or

kilometers per second per second

The citations of the episodes ENT: "Similitude" and VOY: "Elogium" as example usage of the units for acceleration are not valid. In ENT: "Similitude", after the Enterprise (NX-01)'s two shuttlepods were able to start moving the ship out of the polaric field that would eventually indirectly cause every system on the ship to go offline, Travis, the pilot of Shuttlepod 2, did report measurements and acceleration in the same sentence, "Twelve kilometers per hour and accelerating." However, the units of the measurements were for speed, not acceleration. So, what Travis did was report his speed at an instant in time, the instant of his report, and that his speed was increasing over time.

In VOY: "Elogium", when the Voyager (NCC-74656) encountered space-dwelling lifeforms and Paris remarked that they were really moving, Kim confirmed Paris' comment, but as Travis had done in ENT: "Similitude", also reported acceleration and measurements in the same sentence, "He's right. They've accelerated to a velocity of approximately one thousand kilometers per second." But as indicated by the phrase "velocity of approximately one thousand kilometers per second," the measurements were obviously for a velocity. So, in this case, what Kim did was report that the lifeforms had increased their speed over time to a velocity at an instant in time, the instant of his report.

I have therefore replaced the units of measurements, with appropriate ones for acceleration, and deleted the two citations. However, I have not found any episode of Star Trek that mentions units for acceleration, so I could not replace the deleted citations.

-- Astrophysicophile (talk) 07:52, 25 March 2024 (UTC)

Actually, I have found episodes that did mention a unit of measurement for acceleration, but the unit is gravity of Earth or g, rather than metric or English units. For example, in TOS: "The Cage", when Pike asked the ship's geologist about gravity of Talos IV upon the Enterprise's arrival at the planet, the geologist reported the planet's gravity as being 0.9 of Earth.

In another example, in ENT: "In a Mirror, Darkly, Part II", when the Mirror Universe Archer, having lured the Gorn slave master Slar over a specific grav-plating aboard the USS Defiant (NCC-1764), gave Mirror Universe T'Pol a command, T'Pol enhanced the grav-plating to 20 g's.

I have therefore replaced the example units in the article, but included the conversion to the metric system. I have also added citations of a number of episodes, including TOS: "The Cage" and ENT: "In a Mirror, Darkly, Part II".

-- Astrophysicophile (talk) 05:52, 28 March 2024 (UTC)

I have added two more citations of episodes: DIS: "Brother" and TAS: "Beyond the Farthest Star". In DIS: "Brother", when Pike, while preparing his landing pod to be launched from the Discovery, asked Burnham, who was likewise preparing her own pod, if she had flown these pods before, she replied, "Yes, sir. I was one of the test pilots. Nine g's for eleven minutes."

In the Talk:Acceleration#Gravity of Earth section, I described the instance in TAS: "Beyond the Farthest Star".

I have also resorted the measurement citations in chronological order, ignoring whether DIS was in the same time line as TOS and TAS. -- Astrophysicophile (talk) 01:35, 6 April 2024 (UTC)

I believe we generally list citations in release order by series, so I have reordered them accordingly. Also, please note that multiple episodes from a single series may be cited with only one invocation of the appropriate template, i.e.:

{{TAS|Beyond the Farthest Star|Once Upon a Planet}}

instead of

{{TAS|Beyond the Farthest Star}}; {{TAS|Once Upon a Planet}}

For more info on citations, see MA:CYS. 🖖 Mr. Starfleet Command ^{(talk • contribs)} 03:27, 6 April 2024 (UTC)

Gravity of Earth[]

Mr. Starfleet Command, I notice that you changed the metric system conversion of the gravity of Earth (g), from "9.80665 meters per second²" (the standard gravitational acceleration for the surface of the Earth (g_n), by definition, per Wikipedia), to "roughly 9.807 meters per second²." Does Memory Alpha have a guideline that limits the number of significant digits for a physical constant, to a maximum of four? If so, then I prefer changing the metric conversion to "approximately 9.8 meters per second²." -- Astrophysicophile (talk) 08:56, 5 April 2024 (UTC)

You're right, I probably shouldn't have changed it. I've reverted it to the precise measurement. 🖖 Mr. Starfleet Command ^{(talk • contribs)} 12:19, 5 April 2024 (UTC)

Thanks, Mr. Starfleet Command. Live long and prosper. -- Astrophysicophile (talk) 19:57, 5 April 2024 (UTC)

Was that number quoted in an episode or shown on screen? If not, it should likely be simplified and/or shifted off to a BG note. -- Sulfur (talk) 20:02, 5 April 2024 (UTC)

I can't think of a reference off the top of my head. Could someone check if the episodes being cited refer to the number or just "g"? I don't have time right now. 🖖 Mr. Starfleet Command ^{(talk • contribs)} 20:07, 5 April 2024 (UTC)

The metric conversion of g was never quoted in any episode or film. I do not know if any episode or film showed the conversion on screen. I have only looked at a couple of Earth and Federation ship displays that were shown on screen, and as far as I can tell, none of them showed the conversion.

The episodes that I cited only referred to multiples or fractions of g or the gravity of Earth.

Some episodes also referred to multiples or fractions of Earth normal. For instance, in TAS: "Beyond the Farthest Star", when Kirk, Spock, Leonard McCoy, and Scott became trapped in the control center of the Insectoid starship, Spock reported on the environment, "Artificial gravity is in effect here, Captain. Both air and gravity within two points of Earth normal." Now that I have mentioned this, I have added the term "Earth normal gravity" to the article. -- Astrophysicophile (talk) 23:10, 5 April 2024 (UTC)

Well, I've turned the reference into a background note. We can change it back if we find a reference to the number or if one comes up in a future release. 🖖 Mr. Starfleet Command ^{(talk • contribs)} 23:19, 5 April 2024 (UTC)

Sounds good. Thanks. -- Astrophysicophile (talk) 23:26, 5 April 2024 (UTC)

In the background note, I have qualified "gravity of Earth" as "standard gravity of Earth . . . by definition." I have also added a link to the Standard Gravity article at Wikipedia. -- Astrophysicophile (talk) 03:24, 6 April 2024 (UTC)