You can drop a cat from the Eiffel tower and it will survive.

[Glirk Dient]

No. The object will speed up until the drag equals the weight.

Thats what I meant. Typed my post fast and that was the first word that came to mind. I meant weight.

 

[MuToiD_MaN]

Say we have 2 spheres. Both identical in every way except one is twice the size and weight as the other. When dropped they will both have the same T.V. because they are the same shape and have the same air resistance. So what I am saying is just because something is heavier does not mean it will have a higher T.V. Same thing with something lighter. Weight != T.V. Weight comes into play as it will increase or decrese drag.

*foreheadslap*
That's it, I'm outta here.

 

[Glirk Dient]

*foreheadslap*
That's it, I'm outta here.

Mind telling me how 2 objects will have different TV if one weighs twice as much but has twice the drag?

2xweight/2xdrag=#

so...

1/1=1
2/2=1

Hmm...

 

[OCybrManO]

One side is talking about only varying mass. The other side (you) is talking about varying mass and size/shape. Why is there an argument?

 

[Glirk Dient]

Apparently people aren't reading my posts corectly or thoroughly. I am not sure really. Perhaps it's just a bunch of kiddies that want to prove others wrong while they are trying to do something constructive hence enlargening their e-peen.

 

[Feath]

Mind telling me how 2 objects will have different TV if one weighs twice as much but has twice the drag?

Because the drag force depends on the velocity of the object. So if object B has twice the mass of object A then object B would have to fall faster than A for in order for the drag force to equal its new weight. That's assuming that the objects have the same shape of course.

 

[Beerdude26]

Ok thanks, Next time I am falling from the fricken sky I will do that math

Lol, just imagine
You're falling out of an airplane...
You: "65 kg..."
You: "Times three..."
Other person: "aaaaaaaaaaaaaAAAAAAAAAAAAaaaaaaaaaaaa"
You: "Minus 8..."

 

[kirovman]

Do you have to be a jerk about it? Of course you do.

If you read his post:he is 100% right. He didn't say anything at all about the net acceleration of the object. He said that g (acceleration due to gravity) is wholely independant of the mass of the object, which it is. He said NOTHING about how the terminal velocity is independant of the mass, he just said it was "g" that was independant of mass. Which is correct.

Thanks Erestheux Glad to see at least one person reads every word before jumping to conclusions. Drag is an additional acceleration term to the overall equation of an object's motion, it is not gravity.

Here's some reading for people who think they know physics but don't.

Well I know I know Physics if this degree certificate is worth the paper it's printed on. My employers who employ me as a scientist/engineer obviously know that I know physics too.
I suggest you stop treating people in such a hostile way. I meet a lot of people who make mistakes with physics, but I simply make it my aim to educate them, politely correcting them where appropriate and complimenting them on their knowledge so far, rather than to "drum it into their thick skulls" as you so elloquantly put it.

If you want to start getting elitist about physics knowledge, sure I can do that. Our first appointment will be a discussion of the Nuclear Magnetic Resonance of Carbon-13 nuclei and how quantum J-coupling affects their patterns in various hydrogen environments. Bring spectrographs.

 

[Raziaar]

If you want to start getting elitist about physics knowledge, sure I can do that. Our first appointment will be a discussion of the Nuclear Magnetic Resonance of Carbon-13 nuclei and how quantum J-coupling affects their patterns in various hydrogen environments. Bring spectrographs.

My head exploded onto my monitor and keyboard. I managed to type and send this message off before it happened.

 

[Glirk Dient]

Because the drag force depends on the velocity of the object. So if object B has twice the mass of object A then object B would have to fall faster than A for in order for the drag force to equal its new weight. That's assuming that the objects have the same shape of course.

If both objects are at rest and dropped at the same time they will be pulled down at a force of 9.8m/s. Both have the same shape and one is twice as heavy but has twice the drag. That cancels out the weight difference and makes the objects fall at the same speed.

 

[Feath]

If both objects are at rest and dropped at the same time they will be pulled down at a force of 9.8m/s. Both have the same shape and one is twice as heavy but has twice the drag. That cancels out the weight difference and makes the objects fall at the same speed.

There isn't such thing as an object having twice the drag. Drag is an upwards force that depends on the velocity and shape of the object. If both objects are the same shape, the only thing that could change is that the terminal velocity of the heavy one must be more than the lighter one in order to balance out the larger weight.

You seem to be under the impression that there's a formula involving terminal velocity, drag force and weight. There isn't. The terminal velocity is part of the drag force formula.

 

[Blackghost905]

Where is Victomofscience in all this math he is ushally the last nerd standing.

 

[Glirk Dient]

There isn't such thing as an object having twice the drag. Drag is an upwards force that depends on the velocity and shape of the object. If both objects are the same shape, the only thing that could change is that the terminal velocity of the heavy one must be more than the lighter one in order to balance out the larger weight.

You seem to be under the impression that there's a formula involving terminal velocity, drag force and weight. There isn't. The terminal velocity is part of the drag force formula.

I am not talking about shape. I am assuming the shape of one object gives it twice the drag.

I still don't see whats wrong with one object having twice the weight and twice the drag falling at the same speed as the control object.

 

[joule]

Sure the cat'll survive... with a few broken legs of course - as cats do always land on their feet.

 

[Feath]

I am not talking about shape. I am assuming the shape of one object gives it twice the drag.

I still don't see whats wrong with one object having twice the weight and twice the drag falling at the same speed as the control object.

I've really lost what you're asking.

Assuming they're falling through air on the same planet, Two objects will only have the same terminal velocity if

a) They have the same mass and are the same shape.
b) One has a bigger mass and has a bigger surface area.
c) One has a bigger mass and is shaped so it has a higher drag coeffiecient.

If you're asking if two objects can have the same terminal velocity if they have the exact same shape BUT the masses are different. Then no, they can't if they're both falling through the same fluid with the same value of g.

 

[Glo-Boy]

It's not true. Whoever fell for that needs to go back to 8th grade physical science and use some common sense. The cat f-cking dies.

 

[Ikerous]

It's not true. Whoever fell for that needs to go back to 8th grade physical science and use some common sense. The cat f-cking dies.

Why would someone post that 18 pages into a thread without making or addressing a single point...

 

[Feath]

Why would someone post that 18 pages into a thread without making or addressing a single point...

Because he's a rebel that plays by his own rules?

 

[Glo-Boy]

Because I read the first page and posted. I'm not reading 18 pages.

 

[Ikerous]

Because I read the first page and posted. I'm not reading 18 pages.

If you don't read the discussion then don't come in with comments like anyone who thinks the cat would live "needs to go back to 8th grade physical science and use some common sense" when you're probably completely wrong and havent read any of the points ><

Lol, it's just a pet peve of mine, feel free to ignore me

 

[OCybrManO]

Because I read the first page and posted. I'm not reading 18 pages.

If you had read the rest of the thread you might have picked up some of the more important statistics... such as this one: Cats falling from over 9 stories have a survival rate of about 95%.

 

[Dan]

But the problem with that study is that this is based on veterinary hospital accounts of cats falling out of buildings and being treated. I'm sure not many of the dead cats get sent to the hospital so we never find out about those. The dead cats just get shoveled into the dumpster while those that survive or have some chance of survival get reported so the accounts are biased.

 

[OCybrManO]

True, but the conclusion based on the vet data also depends on the trend in the severity of the cases they see among the survivors of the initial fall. If it was as high as a 50/50 shot of being killed by the impact itself (rather than hours later due to injuries) the cats that actually made it to the vet probably wouldn't survive 19 times out of 20. It would probably be quite the opposite. If 95% of the ones they see survive and you're counting the hypothetical situations of cats being killed on impact and don't need to be taken to the vet, there are probably also cases on the other end of the spectrum where some cats come out completely unscathed. At worst, it still hints that falls from 9 floors or higher are highly survivable for cats... if not 95% survivable.

 

[Glirk Dient]

I've really lost what you're asking.

Assuming they're falling through air on the same planet, Two objects will only have the same terminal velocity if

a) They have the same mass and are the same shape.
b) One has a bigger mass and has a bigger surface area.
c) One has a bigger mass and is shaped so it has a higher drag coeffiecient.

If you're asking if two objects can have the same terminal velocity if they have the exact same shape BUT the masses are different. Then no, they can't if they're both falling through the same fluid with the same value of g.

No...earlier people were saying terminal velocity relys solely on weight. I provided an example on where 2 objects with different weight(due to surface area) would have the same TV. I still don't understand why you and a few others keep saying it is wrong. You just defined what I have been saying in my past 20 posts.

 

[jverne]

Thanks Erestheux Glad to see at least one person reads every word before jumping to conclusions. Drag is an additional acceleration term to the overall equation of an object's motion, it is not gravity.


Well I know I know Physics if this degree certificate is worth the paper it's printed on. My employers who employ me as a scientist/engineer obviously know that I know physics too.
I suggest you stop treating people in such a hostile way. I meet a lot of people who make mistakes with physics, but I simply make it my aim to educate them, politely correcting them where appropriate and complimenting them on their knowledge so far, rather than to "drum it into their thick skulls" as you so elloquantly put it.

If you want to start getting elitist about physics knowledge, sure I can do that. Our first appointment will be a discussion of the Nuclear Magnetic Resonance of Carbon-13 nuclei and how quantum J-coupling affects their patterns in various hydrogen environments. Bring spectrographs.

ehh...quantum physics sux!

 

[Muffin Man]

It's not true. Whoever fell for that needs to go back to 8th grade physical science and use some common sense. The cat f-cking dies.

somebody needs to go back to 5 years old (considering your probably only 8 as it is) and get some social skills.

 

[Feath]

No...earlier people were saying terminal velocity relys solely on weight. I provided an example on where 2 objects with different weight(due to surface area) would have the same TV. I still don't understand why you and a few others keep saying it is wrong. You just defined what I have been saying in my past 20 posts.

Terminal velocity doesn't really solely on weight. That's why parachutes work.

 

[TheSomeone]

Who said terminal velocity relies only on weight? It relies on shape, projected area, air friction, and probably other factors I'm not aware of.

 

[Raziaar]

Let me be the first to say, "Nerds".

 

[Greatgat]

Let me be the first to say, "Nerds".

Can I be second? N3rdz.

See, the irony is obvious, as I am using so called "1337-speke" to bring attention to a gross social- ohnevermind.

 

[Glirk Dient]

Terminal velocity doesn't really solely on weight. That's why parachutes work.

Exactly what I have been saying. Weight and surface area are what creates drag...not just weight.

 

[dream431ca]

Exactly what I have been saying. Weight and surface area are what creates drag...not just weight.

You are right..but wrong at the same time. surface area does have an effect, But you forgot the most important fact about terminal velocity....air density. If you have more air, your terminal velocity will be slower. So it's mainly air resistence.

Now consider if you were to drop a cat from the empire state building without any air, then the cat would not live when it hits the ground because there is no terminal velocity. It would just keep on accelerating at 8.1 m/s. The height of the empire state building is 381 meters. So that cat would hit the ground at: 3086 m/s which converts to: 6903 miles per hour..so say bye bye cat.

 

[Glirk Dient]

Yeah...however when your reaching the ground the air gets denser and won't matter since we are talking about when you hit the ground.

Surface area does matter as the more surface are the more friction against the air there is.

 

[kirovman]

Yeah...however when your reaching the ground the air gets denser and won't matter since we are talking about when you hit the ground.

Surface area does matter as the more surface are the more friction against the air there is.

I don't think the air at the ground is significantly denser than the air at the top of the tower. I think you could approximate the air density as constant, and get a reasonably accurate answer.

 

[Sparta]

Here's a question.

What if you tie an anvil to the cat?

What if you strap a piece of buttered toast on the cats back, butter side up?

 

[Raziaar]

Here's a question.

What if you tie an anvil to the cat?

What if you strap a piece of buttered toast on the cats back, butter side up?

The cat would land sideways with the toast... cause toast always land top side down, and cats always land right side up. They'd struggle and their powers of physics would be equal. So the cat would rotate sideways and splat.

 

[Solaris]

Here's a question.

What if you tie an anvil to the cat?

What if you strap a piece of buttered toast on the cats back, butter side up?

You would have made yourself a tasty treat.

 

[Glo-Boy]

somebody needs to go back to 5 years old (considering your probably only 8 as it is) and get some social skills.

Says the nerd who has 600 and some posts in two months, and is no doubt much younger than I, nor will he have a real girlfriend until his late 20s or possibly early 30s. Speaking of fake girlfriends, go back and chat with your online girlfriend who likes eating and unicorns.

 

[Glo-Boy]

If you don't read the discussion then don't come in with comments like anyone who thinks the cat would live "needs to go back to 8th grade physical science and use some common sense" when you're probably completely wrong and havent read any of the points ><

Lol, it's just a pet peve of mine, feel free to ignore me

Spelling and grammatical errors are huge pet peeves of mine too.


EDIT: And by the way, the cat dies. Hands down. F-cking throw YOUR cat off of a building and see what happens. You won't, that's right, because you don't want it to die.

 

[Glirk Dient]

I don't think the air at the ground is significantly denser than the air at the top of the tower. I think you could approximate the air density as constant, and get a reasonably accurate answer.

Yeah...but in one of my examples you were dropped from 10k. The air is thinner up there but it won't matter because the air gets denser the farther you go down...so as you said we might as well keep air density as a constant.