Terminal velocity?

I was wondering if terminal velocity is true then there is no way with out a launch coasters can get past 120 MPH down a hill. Am I right or is there a catch to this scientific fact? In thery then if Terminal Velocity is true you could have a 1000 foot coaster and it would only go 120?

Teminal velocity refers to the maximum velocity of an object in freefall due to friction caused by air.

The amount of drag on an object in freefall has to do with its mass and the surface area of the object.

Grab a feather and drop it from a few feet up. Does it hit 120mph? No, that's because it is very susceptible to the effects of the atmosphere. Now drop a more dense object the same size... say a quarter. Does it fall at the same rate? No. It's more massive, therefore less affected by the drag of the air.

All objects have a terminal velocity in freefall. Not all of are the same.

So, to answer your question about a terminal velocity on a coaster. Yes, it's possible that one day we may hit a point where a coaster simply cannot go any faster without help from a launch, but 120mph won't necessairally be that point.

Sorry, John - wrong, wrong wrong! 120 mph IS the terminal velocity for everything in the known universe(especially Kingda Ka, which will launch upwards at 128 but only come down at 120, to quote Hawking himself.)

I'm sure this clears everything up.

-Skydiving Jeff
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personal max speed in freefall: 240mph

So wait a minute...if 120 mph is the terminal velocity for everything in the known universe, how did you have a max freefall speed of 240 mph?

Hydraulic launch? :)

cedarit said:
Sorry, John - wrong, wrong wrong! 120 mph IS the terminal velocity for everything in the known universe(especially Kingda Ka, which will launch upwards at 128 but only come down at 120, to quote Hawking himself.)

I'm sure this clears everything up.

-Skydiving Jeff

120 is the terminal vesocity for a person falling. pennys are 60.so everything is different.

Yeah but the max you can go is 120 with only the help of gravity. Right?

Yes, but if you have two pennies (remember, 'pennys' are worth 60), you can add them to your 120 to get 240. Basic physics, really.

-Skydiving Jeff
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Terminalvelocity Ill

Now im lost thats ok im gonna think now that coasters will never reach more than 120 without a launch.

I think Skydiving Jeff is being silly on purpose.

Like Michael Darling said, Terminal Velocity is dependant on the surface area, mass, and coefficent of friction of the falling object. Why do you think missiles and airplanes are shaped the way they are? Why do you think they're highly polished metal or paint?

CP4eva'04,

I was just messin'... to reiterate what Michael Darling mentioned above, there is no such thing as a universal constant for terminal velocity. The '120mph' value has become the scapegoat for falling objects everywhere when in reality, that number was merely based on the average falling speed of a human body in freefall (in a flat, belly-to-earth position). Factors such as body position, a person's weight, and even the clothes one is wearing will affect that freefall speed. What a drag indeed!

Consequently, as you may have already figured out, a roller coaster train is NOT a human being -- and thus is not subject to the exact conditions above. Given enough height from which to fall and generate enough speed, the train will eventually accelerate to the point where friction from both the wheels meeting the track, as well as the overall surface area of the train moving against a fluid (air), negates further acceleration -- this is called terminal velocity.

In a nutshell, remember: the max speed of a coaster is 120 mph = complete myth.

-Skydiving Jeff
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Defending the laws of physics when he's not defying them

"Terminal Velocity" - The speed a person is traveling right before they hit the ground after their shoot does not open.

Shoot, your chute didn't open? Sh!T!

I guess this would be as a good a thread as any to put this question in. I got to thinking a couple days ago about the "Hands Down" requirement on TTD. The most obvious reason would be that the launch would cause injuries to people with their hands up.

I then started wondering, would the resistance caused by an entire train who put their hands up be enough to cause a roll-back? This would seem to be an almost bigger reason (at least from a capacity perspective) for having people keep their hands down. I think it would be pretty cool if you could get an entire train to throw their hands up just after launch and cause the train to roll-back. Then your next launch, it would compensate and you could get whipped over the top. Anyone know if this could also be a possibility?

tambo said:
"Terminal Velocity" - The speed a person is traveling right before they hit the ground after their shoot does not open.

Wrong.

From the Wikipedia.org article Terminal Velocity
The terminal velocity of an object falling towards the ground is the speed at which the gravitational force pulling it downwards is equal and opposite to the atmospheric drag (also called air resistance) pushing it upwards. At this speed, the object ceases to accelerate downwards and begins to fall at constant speed.

Read the rest of the article. You might learn something.

Why is such a basic concept of physics so hard for so many folks to understand?

[Edit: apparently POP Forums don't like urls in quotes...] *** Edited 12/16/2004 7:53:13 PM UTC by Michael Darling***

John, in some ways he was right, if you fall from far enough up.

tambo said:
"Terminal Velocity" - The speed a person is traveling right before they hit the ground after their shoot does not open.

Well that's morbid.

JuggaLotus said:
John, in some ways he was right, if you fall from far enough up.

Huh?

cedarit just said, two lines above:
Well that's morbid.

Thankfully, fatalities from equipment malfunctions are very rare these days.

As for the question regarding everyone holding up arms on TTD, I suppose *anything* is possible with that ride (cough, getting stuck at the top, cough), but my intuition tells me that the air resistance generated by the added surface area would be negligible given the train's momentum. Plus, past experience trying to test that theory tells me that even while being on a train where 10 of us held our hands up or leaned out to the side (and failed miserably, I might add), it'll probably never happen.

A few friends have jokingly suggested I take my parachute on the train to get a rollback; on the other hand, I'd prefer not to have my body ripped out of the train from the impact, thank you very much.

-Skydiving Jeff
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"Intamin should make skydiving planes -- then it wouldn't matter if people fell out!"

Man, you guys take this sh&t seriously huh? My original post was meant to be tongue in cheek, except for my unfortunate misspelling which was so quickly jumped upon. (Very nice Chief Wahoo).

I could care less about Terminal Velocity let alone basic physics, Mr. Darling. I leave that to the serious coaster enthusiasses.