Holding a cup of water in a giant drop.

[Epic Fail]

I say it's the jerking motion of the hand when you start to fall, if the cup is secured to the ride, there shouldn't be water coming out.

 

[91TTZ]

Originally posted by: LTC8K6
The inertia of the water and the coin cause them to rise up, imo.

They tend to remain still, and they are not connected to the ride, so their inertia makes them stay still until gravity overcomes their inertia and they begin to free fall.

This is dead wrong.

All of the objects falling on that ride deal with the same physics, and all will tend to fall at the same rate. It's not like the water was subject to a lot of wind resistance when it's inside that cup.

 

[91TTZ]

Originally posted by: LTC8K6
Hold a cup of water in your hand and move the cup downwards rapidly. The water comes out. Inertia.

That would be an example of inertia causing it, but the ride and everything on it are falling due to the force of gravity, and all objects fall at the same rate due to gravity.

 

[dug777]

He shakes it out.

 

[LTC8K6]

It's clearly and obviously inertia, imo.

If you glue the cup to the seat so there is no arm shaking, the same thing will happen.

 

[Gibsons]

Originally posted by: LTC8K6
It's clearly and obviously inertia, imo.

If you glue the cup to the seat so there is no arm shaking, the same thing will happen.

Only if it's initially pushed, and not simply dropped. Like spidey said, if it's just a drop, everything falls at the same rate.

 

[dug777]

Originally posted by: LTC8K6
It's clearly and obviously inertia, imo.

If you glue the cup to the seat so there is no arm shaking, the same thing will happen.

I don't think you are right.

At rest, the water has no 'vertical' inertia.

When you are accelerated downwards by gravity, the cup and the water are acted upon by exactly the same force, so they'll fall at exactly the same speed.

Water only comes out of the cup because something acts upon it against the pull of gravity.

If you put water in a mug, then drop it, no water comes out until it hits the ground (assuming you release it smoothly and on a level.)

Water comes out when you wildly swing a cup down because there are forces acting on the water in various directions, and if you accelerate the cup faster than gravity, there's nothing to stop the water from coming out the top, as it is only accelerating as fast as gravity and the friction from the water touching the side of the cup.

 

[LTC8K6]

Water does form a ball when it is weightless. That could also be part of the solution.

I'm sticking with inertia as the reason things seem to rise, though. Like your arms, or a coin, or water in a cup.

 

[LTC8K6]

One question that I see is this.

Is the cup free falling, or is it being pulled down by the car because it is attached to it?

Is there a conveyor belt involved?

 

[Modelworks]

Water has way more things going on in a fall than just inertia.

When the cup falls the top of the surface of the water is going to want to stay together because of the air pushing down on it and having to break the surface tension before the water can move up.

Water being a liquid is going to want to cling to the cup.

Then you have the molecules that collide with each other as the water moves around and changes shape. As the shape changes so does the surface tension, changing the results again.

Put a ball bearing in the cup and you will get totally different results, nothing like using a liquid.

 

[LTC8K6]

"Water has way more things going on in a fall than just inertia."

That's true but we need to keep it simple for this discussion.

 

[NuclearNed]

Some of those free-fall rides accelerate the passenger faster than the normal acceleration due to gravity. I think Disney's Tower of Terror is an example of one that does this.

 

[LTC8K6]

"Some of those free-fall rides accelerate the passenger faster than the normal acceleration due to gravity."

That's true. Some of them are described as simulated free fall rides because they are not true fee fall.

 

[dug777]

Originally posted by: dug777

Originally posted by: LTC8K6
It's clearly and obviously inertia, imo.

If you glue the cup to the seat so there is no arm shaking, the same thing will happen.

I don't think you are right.

At rest, the water has no 'vertical' inertia.

When you are accelerated downwards by gravity, the cup and the water are acted upon by exactly the same force, so they'll fall at exactly the same speed.

Water only comes out of the cup because something acts upon it against the pull of gravity.

If you put water in a mug, then drop it, no water comes out until it hits the ground (assuming you release it smoothly and on a level.)

Water comes out when you wildly swing a cup down because there are forces acting on the water in various directions, and if you accelerate the cup faster than gravity, there's nothing to stop the water from coming out the top, as it is only accelerating as fast as gravity and the friction from the water touching the side of the cup.

I'm quoting myself because this is the answer

If anything comes out of the cup, it's because the cup is knocked, or the ride is accelerated faster than it is gravity, as I carefully and painfully explained.

It doesn't matter what is in the cup providing the only force working on it is gravity, it will stay in the cup.

/discussion.

 

[TastesLikeChicken]

The answer is simple.

The ride is not free-fall. It accelerates faster than the speed of gravity initially.

I've worked on rides similar to this for years, like Tower of Terror at Disney World and Tokyo Disney Sea. The acceleration is motor driven in order to provide a brief sensation of weightlessness. If they allowed pure free-fall the ride doesn't last long enough to impart a feeling of weightlessness and it's not nearly as much of a thrill.-

 

[MustangSVT]

Originally posted by: TastesLikeChicken
The answer is simple.

The ride is not free-fall. It accelerates faster than the speed of gravity initially.

I've worked on rides similar to this for years, like Tower of Terror at Disney World and Tokyo Disney Sea. The acceleration is motor driven in order to provide a brief sensation of weightlessness. If they allowed pure free-fall the ride doesn't last long enough to impart a feeling of weightlessness and it's not nearly as much of a thrill.-

now that makes sense!!!!

everything works now

Its funny how many people on this thread would have failed physics . especially the ones that talk about inertia... lol.

 

[bsobel]

Originally posted by: LTC8K6
It's clearly and obviously inertia, imo.
If you glue the cup to the seat so there is no arm shaking, the same thing will happen.

You have clearly not taken or not passed physics.
Bll

 

[thomsbrain]

Without watching:

The person's arm is pushing up to hold up the water against gravity. When the ride drops and the passengers go into free fall, there is no need to apply any force upward to keep one's arm level, since everything should initially fall at the same rate. So now the person's arm is pushing up against "no" resistance. The arm jumps for a moment until the person reacts and stops pushing up their arm and pulls it back down. The water jumps along with the arm but there is nothing to pull it back down. So it would be easy for a person to jossle the cup enough to spill.

As others have said, a perfectly still cup on a perfectly free-fall ride will not spill any water.

 

[silverpig]

This is another typical ATOT physics problem. In a perfect world the water would not move. In the real world there are other things which cause it to move.

 

[Slickone]

Originally posted by: TastesLikeChicken
The answer is simple.

The ride is not free-fall. It accelerates faster than the speed of gravity initially.

I've worked on rides similar to this for years, like Tower of Terror at Disney World and Tokyo Disney Sea. The acceleration is motor driven in order to provide a brief sensation of weightlessness. If they allowed pure free-fall the ride doesn't last long enough to impart a feeling of weightlessness and it's not nearly as much of a thrill.-

That's not true. While the Tower of Terror is a faster than freefall drop, the Intamin made Gyro Drop in the video is free fall. It's just like Drop Zone at King's Island and King's Dominion (and a few others).

The Turbo Drop rides made by S&S Power, like Power Tower at Cedar Point, also faster-than-freefall drop rides since compressed air is used to force the car down.