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Post by gato on Jan 9, 2024 6:49:55 GMT -5
A few years ago, I accidentally nudged my iPhone (no protective case) off the corner of my desk, and it hit the tile floor, with a wince inducing thud. That fall of 26 inches cracked the screen. Dang! Off to Staples for a quick (not cheap) fix. On the plus side, this incident has made me much more careful about the proximity of my flailing elbows to the Apple device.
Now, this morning, I read that not one but two iPhones survived after being blown out of that Alaska Airlines jet, and falling 16,000 feet. And not just survived ... but thrived, without even a cracked screen!
Sir Isaac Newton, back in 1666, did some experimenting with his own Apple, to cobble together a checklist of gravitational laws. In his case, he was also able to eat the Apples that failed his gravity challenge.
Historical note: Newton was never able to explain how a screwdriver, dropped from any height in a garage, will roll under a car and smugly settle with folded arms, in the exact center, daring the owner to come after it.
Fast forward to 2024, and it turns out that:
“If the phone is falling with its screen facing the ground, there’s quite a lot of drag, but if the phone is falling straight up and down, there’s quite a bit less. In reality, the phone would be tumbling quite a bit, and get quite a lot of wind essentially giving an upward force.
The terminal velocity of a large screen-down iPhone, would be about 30 mph. The larger the iPhone, the lower the terminal velocity. The maximum is around 100 mph, but that would only happen if the phone’s screen was perpendicular to the ground.” (NYT)
Of course, this learned explanation doesn't factor in my flailing elbows or tile floor. Or why Staples charges so much for a screen repair.
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Post by slacker 🐨 on Jan 9, 2024 11:08:23 GMT -5
There's a lot of factors involved in how a smartphone fares when dropped. The two biggest are quality of the case and how it's positioned when it hits the ground. Hitting on corners is generally bad, but less so with a case that has nicely protected corners. Most Otterbox cases, for example, have very nice rubber protectors on the corners.
Falling face down is usually bad, but again, a case with edges that sit proud of the screen surface (rubberized even better) help, but dropping outside on the one rock within 10' will do a number on it.
I've dropped my phone about 20 times over the last decade....every time without incident. I'm very particular about my cases. My daughter just buys cases that look cool....she smashed her screen on the first drop.
I've had great luck with Otterbox and Spigen cases. Pretty much my go-to anymore.
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Post by Leftee on Jan 9, 2024 11:26:28 GMT -5
I use Spigen cases and I have never so much as cracked a screen. I’ve been on iPhone for 10 years now.
Now watch… I’ve probably jinxed myself.
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chucksmi
Wholenote
Posts: 173
Formerly Known As: Offshore Angler elsewhere
Age: I saw Jerry Live
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Post by chucksmi on Jan 9, 2024 12:45:26 GMT -5
Actually the coefficient of drag is dependent upon the phone's orientation relative to its velocity vector. The force of the drag is dependent on the phone's velocity, altitude and coefficient of drag. The phone's terminal velocity is highly dependent upon altitude. If we dropped it from 100,000 feet it would become supersonic, and then slow to subsonic as it dove into the more dense atmosphere as it approached the earth.
The total acceleration of the phone would be its mass times the local acceleration due to gravity (a function of geographic location and altitude) minus the drag coefficient times the dynamic pressure (function of altitude, pressure and temperature and the square of the velocity.)
Of course this doesn't take into effect and convective up or down drafts it may encounter, some updrafts may even be strong enough to lift the phone away from the earth's surface. Not to mention any aero effects if would have as it encountered crosswinds from the jet stream.
So we would need to use a numerical technique which randomized the phone's orientation for each step to do an integration of the phone's velocity over time, and we woudd then take each numerical step to determine its altitude so we knew what values to use for the variables.
So yeah, I used to be a rocket engineer if you can't tell.
Chuck
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Post by tahitijack on Jan 9, 2024 12:52:08 GMT -5
I've used Otterbox cellphone cases for years. A few dops along the way but never a cracked screen or any significant damage. Cellphone cases are money well spent and just a fraction of the cost of the new cell phone or replacement screen.
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Post by gato on Jan 9, 2024 15:05:05 GMT -5
Actually the coefficient of drag is dependent upon the phone's orientation relative to its velocity vector. The force of the drag is dependent on the phone's velocity, altitude and coefficient of drag. The phone's terminal velocity is highly dependent upon altitude. If we dropped it from 100,000 feet it would become supersonic, and then slow to subsonic as it dove into the more dense atmosphere as it approached the earth. The total acceleration of the phone would be its mass times the local acceleration due to gravity (a function of geographic location and altitude) minus the drag coefficient times the dynamic pressure (function of altitude, pressure and temperature and the square of the velocity.) Of course this doesn't take into effect and convective up or down drafts it may encounter, some updrafts may even be strong enough to lift the phone away from the earth's surface. Not to mention any aero effects if would have as it encountered crosswinds from the jet stream. So we would need to use a numerical technique which randomized the phone's orientation for each step to do an integration of the phone's velocity over time, and we woudd then take each numerical step to determine its altitude so we knew what values to use for the variables. So yeah, I used to be a rocket engineer if you can't tell. Chuck Any idea what my phone's velocity was, falling 26 inches? |
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chucksmi
Wholenote
Posts: 173
Formerly Known As: Offshore Angler elsewhere
Age: I saw Jerry Live
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Post by chucksmi on Jan 9, 2024 18:05:32 GMT -5
Back of the napkin calc, assuming air resistance is negligible at low velocity - I get just over 8 mph.
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Post by gato on Jan 10, 2024 5:39:58 GMT -5
Back of the napkin calc, assuming air resistance is negligible at low velocity - I get just over 8 mph. Hmmm ... so the mini parachute I designed didn't have time to deploy. |
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chucksmi
Wholenote
Posts: 173
Formerly Known As: Offshore Angler elsewhere
Age: I saw Jerry Live
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Post by chucksmi on Jan 10, 2024 14:31:59 GMT -5
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chucksmi
Wholenote
Posts: 173
Formerly Known As: Offshore Angler elsewhere
Age: I saw Jerry Live
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Post by chucksmi on Jan 10, 2024 14:34:28 GMT -5
It would have to deploy before .367 seconds and still have time to be able to decelerate the phone. I'm going to guess that such a device would cost a lot more than the phone.
Chuck
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Post by slacker 🐨 on Jan 10, 2024 14:59:18 GMT -5
It would have to deploy before .367 seconds and still have time to be able to decelerate the phone. I'm going to guess that such a device would cost a lot more than the phone. Chuck Maybe if you had it attached and deployed all the time...just have it dangling from your phone 24/7. What diameter would be sufficient to slow it down enough to mitigate damage when dropped? Oh, and can a plane take off from a treadmill that always goes equal speed in reverse to the speed of the plane? |
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Post by gato on Jan 10, 2024 15:57:46 GMT -5
It would have to deploy before .367 seconds and still have time to be able to decelerate the phone. I'm going to guess that such a device would cost a lot more than the phone. Chuck Maybe if you had it attached and deployed all the time...just have it dangling from your phone 24/7. What diameter would be sufficient to slow it down enough to mitigate damage when dropped? Oh, and can a plane take off from a treadmill that always goes equal speed in reverse to the speed of the plane? Sure, as long as no passengers are holding their breath. That really gums up the works. |
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chucksmi
Wholenote
Posts: 173
Formerly Known As: Offshore Angler elsewhere
Age: I saw Jerry Live
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Post by chucksmi on Jan 11, 2024 6:40:28 GMT -5
It would have to deploy before .367 seconds and still have time to be able to decelerate the phone. I'm going to guess that such a device would cost a lot more than the phone. Chuck Maybe if you had it attached and deployed all the time...just have it dangling from your phone 24/7. What diameter would be sufficient to slow it down enough to mitigate damage when dropped? Oh, and can a plane take off from a treadmill that always goes equal speed in reverse to the speed of the plane? The wheel speed has nothing to do with the airspeed. The airplane would take off just fine on a treadmill. In fact, the airplane could take off going backwards on the treadmill if there was sufficient wind velocity. |
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Post by slacker 🐨 on Jan 11, 2024 10:23:12 GMT -5
Maybe if you had it attached and deployed all the time...just have it dangling from your phone 24/7. What diameter would be sufficient to slow it down enough to mitigate damage when dropped? Oh, and can a plane take off from a treadmill that always goes equal speed in reverse to the speed of the plane? The wheel speed has nothing to do with the airspeed. The airplane would take off just fine on a treadmill. In fact, the airplane could take off going backwards on the treadmill if there was sufficient wind velocity. Agreed, but I was amazed how many people at the old FDP couldn't grasp that. IIRC, that was a 20 pager or so and still there were some that were dead certain it couldn't take off. |
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chucksmi
Wholenote
Posts: 173
Formerly Known As: Offshore Angler elsewhere
Age: I saw Jerry Live
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Post by chucksmi on Jan 11, 2024 12:09:35 GMT -5
The wheel speed has nothing to do with the airspeed. The airplane would take off just fine on a treadmill. In fact, the airplane could take off going backwards on the treadmill if there was sufficient wind velocity. Agreed, but I was amazed how many people at the old FDP couldn't grasp that. IIRC, that was a 20 pager or so and still there were some that were dead certain it couldn't take off. LOL, it's too easy to explain. Just ask them what would happen when the same airplane landed on the treadmill. |
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Post by LTB on Jan 12, 2024 7:44:20 GMT -5
I use and have used Otterbox Defender series case with Mag Safe (for WIFI charging) for my iPhones along with a screen protector. I have dropped my phone from 3 to 5 feet with no issues multiple times (Yes I exhibit clumsiness, lol )
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