Attraction Source Forum

Ok title says it all really. But let's say it was possible to fall from the exact some height as oblivion at the exact same time. Which would hit the tunnel first? I think it's oblivion. Purely because you feel like your pushed back into your seat when you fall, but if you were falling faster wouldn't you stay rested against the bars? Im going to hope someone with mathematical knowledge can work out the velocity and weights etc to see which it is.

No, because for one you aren't falling straight down due to traversing a curved bit of track instead of falling straight through space, also you aren't propelled down the drop in any way so the sensation of being pushed into the back of your seat is just the train traveling around the curve towards the floor and taking you with it. If anything, you fall slower than true 0G because of the above, and also there is friction in the wheel assemblies and stuff on the train that would prevent you from accelerating that quickly.

Well in general all objects fall at 9.81ms (gravitational pull), but if you take into account mass of the objects, this will effect air resistance and there will be a slight difference in time, but not much.

Bear wrote: No, because for one you aren't falling straight down due to traversing a curved bit of track instead of falling straight through space, also you aren't propelled down the drop in any way so the sensation of being pushed into the back of your seat is just the train traveling around the curve towards the floor and taking you with it. If anything, you fall slower than true 0G because of the above, and also there is friction in the wheel assemblies and stuff on the train that would prevent you from accelerating that quickly.

True but the mass of the car and all people on it will have greater effects on terminal velocity than just an average sized man. And resistance in the wheels is minimal especially when talking about the weight of an oblivion car.

Friction and air resistance will have a big part to play here. However, the weight of the shuttle is a hell of a lot greater than that of one person.

You are right though, Bear, the path of the track is not a straight line towards the ground. I suspect this has a bigger impact on the speed than other factors.

Where's John or Islander when you need them?

In your question are you following the same path as Oblivion? If you are then you should land at roughly the same time, for the reason SamJ gave; gravity pulls things at the same speed. If anything I imagine you'd land first, due to the air resistance on the shuttle and the friction in the wheel clusters and between the wheels and track, but only fractions of a second earlier though.

If you are falling straight down then you would land first, a straight line is the fastest path from point A "mid-air" to point B "the ground", again the weight has no bearing for the reasons above.

There's only one way to settle this. Push someone off the top of the catwalk at the same time as a shuttle drops. :evillaugh:

In a vacuum with no external forces you will both hit the ground at the same time regardless of the trajectory....

unfortunately there are many variable factors for example the friction on the track, the air resistance on the trains and wind to name a few,

the only answer to give really is the example in a vacuum, X-sector is not in a vacuum unfortunately...

mass plays no effect in speed only momentum.

Interesting question, but I honestly don't know.  In a vacuum, the human would hit first as obviously Oblivion isn't quite vertical and therefore would accelerate very slightly slower, but throw in air resistance and it becomes a lot more interesting. 

In theory a heavy object falls at the same speed as a lighter one, but a golf ball accelerates faster than an equal size table tennis ball as the denser golf ball can push the air out of the way more easily (note that both size and weight affect acceleration - a crumpled piece of paper falls faster than an uncrumpled one).  Even with the slight angle of the track and the resistance of the wheels, I suspect the huge weight and density of an Oblivion shuttle would allow it to accelerate quicker once over the initial curve, but this is only a guess.

If we assume that the shuttle will accelerate faster than the person would once it gets past the initial curve, it only has until the car starts reaches the hole to catch up with the human, as the acceleration rapidly falls away as the track levels off.  I suspect that the head start a falling person has will be enough to see them reach the hole first, but with a longer drop that could be reversed.

One thing we can be sure of is that Oblivion takes longer to fall it's full 180ft than a person would, as the bottom half of the drop is curved and the acceleration rapidly diminishes, a luxury a falling human wouldn't be offered.

Well a shuttle drops faster than a droplet of sweat, we know this much.  :P

Yes,
We know from stats that oblivion's top speed is 68 mph, which must be at the bottom of the drop.
The height of the drop is 180 ft or 54 metres.
A person falling has very little air resistance so I shall ignore this.

The speed of impact is the square route of 9.81 * height,

sqrt(9.81*54) = 23.01 m/s = 51.47 mph

This is obviously less than blivvys top speed. If I accounted for air resistance it would only make the figure lower.

So in conclusion yes, oblivion does fall faster than a person from the same height

if you have a heavy object in your hand and you start jumping with it holding it loosely (on a trampoline or something) do you feel like you are pulling the object? -
gravity pulls everything down at the same speed but I would say that you definitely feel like you are pulling the object but no idea whether thats down to air resistance acting harder on the heavy object or because free fall is identical to weightlessness which causes objects to wonder.

(please don't do this experiment with a heavy object or scissors or something crazy like that - use a tennis ball or something soft)

When things are in free fall its the same as floating in space if the person and the ride car is in free fall then its as if they are floating in space - neither pulling/pushing the other cause both are 0 grams in weight. But is oblivion true free fall? As soon as you get a change in direction and the different weights/masses comes back into play.

I guess the important things here are that in true free fall everything falls at the same speed - Oblivion, rider, plane, pilot, debris - and it falls like its floating in space.

It does feel as if Oblivion is pushing you a bit but if it was giving you any more than a slight force (like the 2 or 3 tonnes its probably weighs) you would really know about it - like with Rita.

The reason for the push is down to 1 of 2 things, its either the air resistance acting on your body (pushing you back into the seat) or its any change in direction that deviates from a full vertical drop - need a physicist here?

kingbling11 wrote: The speed of impact is the square route of 9.81 * height

Not quite right - the speed is given by the square roof of (2 * g * h), which gives a theoretical speed of around 73mph.

This doesn't help answer the question though, as the acceleration is not constant due to the track gradually leveling out.

It might be worth taking a look at the teachers resources section of the AT website, I seem to remember there were some forces worksheets on there at one time, and I'm sure they looked at some aspects of Oblivions' drop, but I'm afraid I don't remember exactly what!

There are several factors that are relevant and significant.

Suppose x-sector was in a vaccum and the track had zero friction and was at 90 degrees then most would agree that both object would fall at the same rate and land at the ground at the same time. Then most people would be wrong. The inertia (resistance to change in velocity due to an acting force) of the oblivion car at zero velocity is much higher than a person due to inertia being dependant on mass.

Lets now allow the people riding oblivion to breathe and add air into x-sector but keep the track at 90 degree with zero friction. What we need to do know is work out the terminal velocity of the car and of a person. Fortunately there is a handy website http://www.grc.nasa.gov/WWW/k-12/airplane/termv.html that helps with the calculation. I used 4 tonnes for the oblivion car,  a cross sectional area of 10sqm (imagine front on view so a rough guess), a drag coefficient of 1.28 (flat plat perpendicular to plane of travel) and an altitude of 100m asl. This gives a terminal velocity of the oblivion car of approx 158mph. Obviously it never reaches this  but this is my theoretical maximum for a much larger version of oblivon.

The terminal velocity of a person is approx 120mph (common knowledge).  As a falling body drops through air the drag increases untill the upward pressure equals the acceleration due to gravity and terminal velocity is reached. If an object has a higher terminal velocity than another, then therefore the rate of drag increrase must be slower as the acceleration due to gravity is constant. to illustrate with made up numbers, suppose the drag of the oblivion car increased by 0.1 metres per second per second then the net acceeration would look like this in 1 second increments :- 9.8, 9.7, 9.6, 9.5, 9.4 etc etc.
Suppse for a person the drag increased by 0.2 metres per second per second then the net acceleration would become 9.8, 9.6, 9.4, 9.2 etc etc

As you can see the oblivion car has a higher net acceleration than the person on their own as it has a higher terminal velocity.

As is well known the track is at 88.8 degrees not at 90. this is to stop the car wheels leavnig the track making for a smooth ride as they dont hit the track again, and causes less wear and tear. So this tells us that the oblivion car is never in free fall. But why 88.8, why not 89.2 or 87.6. One could argue that this is the maximum angle to allow the car to be at almost but not quite free fall. due to the calculations for the friction and angle of attack being pretty complex I am going to assume that 88.8 degrees is the perfect angle with minimal slowing on the car (yes this is incorrect).

So my conclusion is that the oblivion car will fall faster than a person without the car due to it having a higher terminal velocoty. The overall efefct will be small though due to the drop length being relatively small.

Badgy

I knew this was a good topic idea so are we saying yes to oblivion falling faster than a human?

Oh and I've added a poll, as I believe it might be good to get people's opinions.

i believe no difference

because if you drop two objects of different mass they land at the same time *strokes moustache*

I'm sure every person I know has posed that question to me whilst in the queue for Oblivion - "If your restraint came undone just after you dropped over the edge, would you fall out of your seat or get pushed back into it?"

King Nemesis wrote: i believe no difference

because if you drop two objects of different mass they land at the same time *strokes moustache*

So if I drop a feather and a lead weight...