iPad SURVIVES FALL FROM SPACE Rugged case manufacturer G-Form sought to prove its hardware protection credentials this week, launching an iPad into space before letting it plummet to Earth. Needless to say, the fondleslab survived the fall - we probably wouldn't write the story otherwise. The company wrapped an iPad in its Extreme Edge case and, using a …
To quote ElReg: "Rugged case manufacturer G-Form sought to prove its hardware protection credentials this week, launching an iPad into space before letting it plummet to Earth. Needless to say, the fondleslab survived the fall - we probably wouldn't write the story otherwise"
Yes you would, the headline would read:
"iPad falls from space and breaks into a gazillion pieces!"
Not because the fondleslab didn't survive the fall, but because it was actually in space!
So what is the terminal velocity of the iPad in one of these cases? Probably fairly low as the case is presumably light and we all know the iPad is too. So dropping it from only 50 feet up might get it striking the Earth at the same speed anyway. Might even save wrecking a perfectly serviceable balloon as well. Sighs...
I can only assume you're not familiar with the what would fall faster, a cannon ball or a feather saying?
Long and short of it is weight has nothing to do with it. Everything is subject to gravity, which with no external forces, will accelerate an object at 9.81m/s/s towards the earth. The external forces relevant in this situation would be friction, which can be greatly enhanced by the addition of a parachute, or even covering the case in deep pile carpet.
In an atmosphere, wind resistance to surface area DOES make a difference, which is why the hammer-and-feather thing was demonstrated on the moon - try it in your living room or off your balcony and you won't get the same result. That is what 'terminal velocity' is all about. If you want the cannonball thing to work down here, you need to pair it up with a same-size sphere of balsa wood (or polystyrine these days is even better).
Interesting asside: a mouse can fall (relatively) safely from any height as its terminal velocity is well below the point at which is would suffer major damage from hitting the ground.
Weight does not come into it... Gravity on Earth accelerates the objects at 9.81m/s/s.
Friction acts in the opposite direction, against gravity.
Surface area is relevant (because of the friction from the air), weight isn't...
You can test it on earth, you just do it in a vacuum to remove the friction component.
Terminal velocity is attained when the force of gravity is equal to the force of friction (i.e. the sum of forces is zero). It is correct that the force of friction does not depend on weight. However, the force of gravity does depend on weight – and so a heavy object will have to fall faster for both forces to be equal. Since the force of friction is roughly proportional to the square of speed, an object that is say four times heavier with the same surface will have a terminal velocity twice as fast.
That is, terminal velocity is the solution of the speed variable in this equation:
9.81 * weight = constant * surface * speed^2
Mathematically, terminal velocity—without considering buoyancy effects—is given by
Vt = Root( 2mg / (pACd) )
where
Vt = terminal velocity,
m = mass of the falling object,
g = acceleration due to gravity,
Cd = drag coefficient,
ρ = density of the medium through which the object is falling, and
A = projected area of the object.
FFS, is this really a techie forum?????????????????????
In scientific usage weight and mass are fundamentally different attributes; mass is an intrinsic property of matter and weight is a force that results from the action of gravity on mass.
Since Force = mass x Acceleration, Weight = mg, where g is the acceleration due to gravity and is measured in Newtons, mass
A falling object is therefore accelerating towards the earth and will continue to do so at initially 9.81 m/s squared. The object be subject to aerodynamic drag (a vector force) in the opposite direction of the acceleration. Drag applies as a log law (go twice as fast and you experience 4 times the drag) and so rises exponentially until the object reaches terminal velocity at which point it will be experiencing a drag (force) which will equal their weight (force).
This drag force is aerodynamic drag and includes form drag (high, iFad is a flat non-aerodynamic surface perpendicular to the airflow), skin friction (low on a nice shiny iFad), interference drag (low because it is a simple shape with propriety rounded corners) and induced or vortex drag (high, see form drag).
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So let me get this clear, you can state something about a product you make and sell and then later on after you have sold some, go onto prove what you said. This is why I'll never do well in buisness. Marketing, law I have a grasp on but this theoretical marketing is something I admit is over my head.
What next, pen's and notebooks that don't need cases to survive this test, whatever next.
It's only 30.48Km which is well short of the 100Km used by the FAI or the 50NM used by NASA for the award of Astronaut wings (there's about 4 miles difference between the two).
It's bad enough people in marketing have redefined the meaning of 'unlimited' don't let them get away with any more abuses.
Uhh... I don't think so. A generally accepted standard is the Karman Line, which is a rough approximation of the point below which "significant lateral thrust would be keep a craft flying level" (from 'Where Does Space Begin?' on Slate). That altitude is 100 kilometers. If Google is to be believed, that works out to 328,083.99 feet.
NASA determines whether you're an astronaut (which it seems would apply to iPads as well as badasses) by using the 100km figure above. The USAF, generously, considers you an astronaut if you've gone up a mere 80km - but that's still far above 100,000 feet.
Not only that, the SR71 Blackbird had a *service ceiling* (normal operating range) of 85,000 feet.
And a final thought - a balloon can only support an object if it can 'float' on the air around it. A balloon, by definition, can't leave the atmosphere any more than a rubber duck can float to the top of the tub water and keep on going until it's hovering. Ye cannae change tha laws'a'physics.
So we have problems:
A: At absolute best, the balloon could 'float on the surface of space'. If you want to get really pedantic, that disqualifies any claims immediately - the iPad is hanging below the balloon, ergo it can't be in space. But that's not necessary...
A: By definition you can't stick a balloon in space, as it will pop. Their balloon did not pop. It did not go into space.
B: The atmosphere's border is gradual, not immediate, like the tub water. Something buoyant will float up to a certain point and stay there; it's 'surface' is dependent on its lift. Have any mass at all? You won't get to the top; at some point your lift (unless you're a rocket) is going to go away, and that point will not be space.
C: Remember, even helium has some mass. If you get to the point where the atmosphere is less dense than helium, as it must, the whole kit and kaboodle might as well be a brick. You want to get to space? Helium may be lighter than air, but I'm fairly sure it isn't lighter than nothing.
So, there's no way in hell it's going to come even close to any commonly accepted definition of 'space'. And it didn't - far less than half by the most generous definition, and less than a third by the most common.
I'm not surprised about the case manufacturer - playing fast and loose with the facts is a treasured tradition of marketing - but I'm a bit surprised that El Reg just gave them a free pass. If someone from the US issued a press release saying that they had driven an electric car "coast-to-coast on one charge, all the way to Chicago!", you'd be all over it like a cheap suit. So I'm disappointed that you didn't jump on -this-.
"I'm not surprised about the case manufacturer - playing fast and loose with the facts is a treasured tradition of marketing..."
Seriously... it would've been equally impressive -- not to mention truthful -- if they'd simply stated that an iPad in one of their cases survived a drop from 100k feet, perhaps mentioning in that context the operational ceiling of such craft as the SR71 or the X15.
...is just that. Once you reach the height at which you (or some object) will be travelling at terminal velocity before you (the object) will hit the ground, it really doesn't matter how much higher you go - you are not going to hit the ground any harder, so it's really just a bit academic whether it was space or not!
While I agree with you on the main thing (100,000 feet isn't space), I've got to point out that:
A) their balloon did, in fact, pop and
B) depending on friction, having a more defined boundary and surface tension, you could get the duck to "hover" - it'll still have a bit of velocity when acceleration drops to zero, so it'll pop out of the tub and fall back under gravity. Let go of a closed empty plastic bottle at the bottom of a swimming pool and watch it fly!
100,000 ft = approx 18ish miles, still below the FAI definition of where "space" starts, iirc.
Needless to say, re-entry heating and dynamic stresses were probably minimal, if any -- if you can even call what the encased iPad went through "re-entry".
A more accurate headline would've been "iPad SURVIVES FALL FROM WICKED-ASSED HIGH ALTITUDE".
Now, if an ISS crewman using an iPad for some function while on EVA accidentally let it get away from him and drift out of reach -- like that toolbag during a Shuttle EVA recently -- _that_ iPad would have absolutely FALLEN FROM SPACE, although not surviving as it would've had no high-impact case around it, and would be re-entering at about Mach 25ish.
iPhone fell 1000 feet and lived eh?
Mine fell 4 feel in a super market and shattered. That was a 3GS, not the new one that lands "buttered side down" all the time with glass on both sides.
There's generally 2 types of iPhones: Ones in a case, and ones with shattered screens.
Gorilla glass is still glass.
I think it would have been a more impressive event if the entire rig had busted apart into uncountable pieces. As it was, the camera came out just as operational as the iPad. Who made the case for that? The bar that was holding the two together sure seemed strong. Was it bent by the impact? Who made that? What about the thing (accelerometer) that was wrapped around the iPad? That seemed to come out in pretty good condition, though they didn't demonstrate it's operational status before or after the fall. And really, if it was an accelerometer, why not use the iPad's? Or is that a different kind of accelerometer? You want to impress me? Calculate it's terminal velocity (call Mythbusters if you need help), drop someone out of a plane with a parachute, and try to hit a target with the iPad in it's case alone. With that long arm, it almost helicoptered to the ground, slowing it's decent. I guarantee you it would have fallen faster without the excess wind resistance. And, with all that other crap attached to it, the force of the landing was distributed across the whole structure. A net book of approximately equal weight would have survived that fall. What a croc.
I noticed that the camera on the bar also surrived the fall (from all of the video they showed from it) and it didn't appear to have a G-Form case on it, so the real question is would the iPad surived like the camera did without the case.
Also putting the GPS tracker on the back side of the case so you know it will fall on it back probably help a lot as well, so you now the the iPad isn't landing on its edge.
Unless I'm mistaken they sent the thing up switched on and it returned to the ground still working?? Forget the actual drop and impact for a moment and consider the temperature. According to apple the operating temperature is 0° to 35° C, non operating -20° to 45° C (http://www.apple.com/ipad/specs/) and according to scientific observation the temperature at > 87,000ft is below -40 on average (http://naca.central.cranfield.ac.uk/reports/1958/naca-tn-4169.pdf unless I'm reading it wrong). I take it this wasn't an independent test.
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