Malaysia Watch Forum
Main Forums => General Discussion - Modern Watches => Topic started by: ck77 on November 06, 2012, 02:19:57 PM
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Colleague's watch dropped from a table. Face down.
Ouch ....
(http://i154.photobucket.com/albums/s246/ongck77/IMG-20121106-WA0001.jpg)
(http://i154.photobucket.com/albums/s246/ongck77/C360_2012-11-06-09-15-21.jpg)
Will send in to Ball service center, most probably the movement need to be clean as well.
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Ummm looks like the crystal has some form of laminate - stops it from shattering completely. Can anyone confirm?
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Keep calm! Everything can still be saved! :Praying: :Praying: :Praying:
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OMG, look like the day date display also got affected... :o
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so much for shock protection :P
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how high was the table from the ground? And also what sort of floor was it?
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safest place for a watch in on the wrist..
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Ouuch!! Sakit hati tengok..May i know what Ball model is that?
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:o :o :o :o noooo ... Not a ball :Blue:
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Shock protection is for the movement NOT the glass.
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how high was the table from the ground? And also what sort of floor was it?
Normal table height I guess, should be marble floor.
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Ouuch!! Sakit hati tengok..May i know what Ball model is that?
This is Ball Ionosphere Chrono.
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Colleague's watch dropped from a table. Face down.
Ouch ....
(http://i154.photobucket.com/albums/s246/ongck77/IMG-20121106-WA0001.jpg)
Will send in to Ball service center, most probably the movement need to be clean as well.
Let's do some simple physics (my first attempt after 23 years)......
Assuming the watch weighs 200g or 0.2kg
Force = mass x acceleration
F= 0.2kg x 10m/s2
F= 2N
The watch fell on its face. I assume the diameter of the dial / crystal is 40mm. Hence the radius is 20mm or 0.02m. Area of the dial / crystal is therefore approx 3.1416 x 0.02m x 0.02m = 0.001256 metre squared.
Pressure exerted ==> P = F/A = 2/0.001256 = 1,592.3 Pascal = 1.5923kPa.
Now, from my memory, 1 ATM is 101.3kPa.
Can 1% of the atmosphereic pressure really crack the crystal like that? Or maybe my physics is rusty beyond help? :laugh:
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Wah Loo, I thought you are a lawyer.
Physics also can :thumbsup:
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Pull out the crown n stop the watch, small debris might enter the movement n also the hands might swipe the debris against the face..
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Wah Loo, I thought you are a lawyer.
Physics also can :thumbsup:
If my calculation is correct, then perhaps the watch did not fall flat on its face, perhaps at an acute angle and onto something sharp. Hence the Area onto which the force is applied is much smaller, meaning the pressure was much much higher. Hence the crack.... ;D
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Is it u fren accidentally step on it after dropped? I dropped my 16610 before from table height and the only damage is the lug dented and the saphire still crystal clear... Not even a scratch
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Is it u fren accidentally step on it after dropped? I dropped my 16610 before from table height and the only damage is the lug dented and the saphire still crystal clear... Not even a scratch
Maybe like enkidu said, is the angle.
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I have dropped watches before from table,well,actually waist height and so far thank my lucky stars no untoward incident.That really looks nasty and hard to imagine that table height can wreak so much havoc
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shit~!! how much it cost to fix the glass?
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Well even the sapphire glass on my AP cost rm300+ to replace.
Aint gonna be that expensive i think.
More worried if the movement damaged much.
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do the crystals on ball watches protrude above the bezel like Rolex watches?
Can 1% of the atmosphereic pressure really crack the crystal like that? Or maybe my physics is rusty beyond help? :laugh:
Now while I cannot confirm the calculations, I would think that although the force of impact may be much lower than absolute atmospheric pressure, it cannot be used as a comparison because both the inside and outside of the watch should be at atmospheric pressure. I'm inclined to think it hit at a point and resonant frequency created at impact is close to the resonant frequency of the crystal and that caused it to shatter.
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do the crystals on ball watches protrude above the bezel like Rolex watches?
Can 1% of the atmosphereic pressure really crack the crystal like that? Or maybe my physics is rusty beyond help? :laugh:
Now while I cannot confirm the calculations, I would think that although the force of impact may be much lower than absolute atmospheric pressure, it cannot be used as a comparison because both the inside and outside of the watch should be at atmospheric pressure. I'm inclined to think it hit at a point and resonant frequency created at impact is close to the resonant frequency of the crystal and that caused it to shatter.
Now that is some serious science. :laugh:
Anyhow, hope that no debris enters the movement. :Cheers:
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Now while I cannot confirm the calculations, I would think that although the force of impact may be much lower than absolute atmospheric pressure, it cannot be used as a comparison because both the inside and outside of the watch should be at atmospheric pressure. I'm inclined to think it hit at a point and resonant frequency created at impact is close to the resonant frequency of the crystal and that caused it to shatter.
2013 Nobel Prize in Physics coming your way next year. :laugh:
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Ouchhh...pray the watch will 'heal' faster...
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Don't think crystal costly...
Few hundred bucks shd b able to cure!!!
Movement not affected right? Running?
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Not sure the extent of the damage, he has yet to send it to service center.
Have advised him to pull put the crown to stop the movement.
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but with the day date misaligned....
i dont think its a easy task to rectify it.... :P
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Aiyoh! Anyway good excuse to upgrade ;)
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Someone should start a thread on physical damage to your watches. Fall, stepped, cooked, frozen, burnt, thrown, abused, knocked, etc.
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My marina militate, one day old fell from my hands face down, and it was gone.... Sigh... So ordered again. :thumbsup:
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Not sure about the time but 7750 does not have quickset date and day ifi remember correctly. So might just be in the midst of date-day change.
but with the day date misaligned....
i dont think its a easy task to rectify it.... :P
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Let's do some simple physics (my first attempt after 23 years)......
Assuming the watch weighs 200g or 0.2kg
Force = mass x acceleration
F= 0.2kg x 10m/s2
F= 2N
The watch fell on its face. I assume the diameter of the dial / crystal is 40mm. Hence the radius is 20mm or 0.02m. Area of the dial / crystal is therefore approx 3.1416 x 0.02m x 0.02m = 0.001256 metre squared.
Pressure exerted ==> P = F/A = 2/0.001256 = 1,592.3 Pascal = 1.5923kPa.
Now, from my memory, 1 ATM is 101.3kPa.
Can 1% of the atmosphereic pressure really crack the crystal like that? Or maybe my physics is rusty beyond help? :laugh:
I think it is related to impulse force it endure rather than the force it has during its fall. Your calculation is based on during its free fall where the acceleration is the gravity. However, when it hits the group, there is a change in momentum.
Take 1m height, acceleration = 9.81 m^2 / sec and initial velocity = 0 m/s
By using one of the kinematics equation, v^2 - u^2 = 2as
v^2 - 0 = 2(9.81)(1)
v = 4.429 m/s at the last moment before impact.
momentum, p =mv = 0.2kg x 4.429m/s
=0.8859 N s
during impact, the watch was stopped almost instantaneously because there wasn't anything slowly it down and for the sake of calculation,
lets say that the impulse time is 1 x 10^-7 s (that is still not exact 0)
0.8859 N s / 0.0000001 s
Then the impulse force would be 8859000N !
let say the WR is 30 bar = 30 x 101.3x10^3 = 3039000 Pa
it means the watch can withstand force of
F = P x A = 303900 Pa x 0.001256 = 3816.984 N
So now you see the logic. If it lands on the carpet, it has more time of slowing done, to let says 0.5s , then the impulse force would be reduced to 1.7718N
Cheers :Cheers:
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Didn't know we have so many engineers and scientists on board :)
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Didn't know we have so many engineers and scientists on board :)
i'm still student ! :D
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Didn't know we have so many engineers and scientists on board :)
i'm still student ! :D
You are right Jeffrey!!! My calculation was flawed in that it only dealt with the force / pressure when the watch is say, resting on a surface, not the impact itself. Yes, it's the change in momentum or more precisely the rate of change of momentum =>
Rate of change = (mv-mu)/t
= m(v-u)/t
=ma
which is the applicable force!!!!
2013 Nobel prize in Physics jointly awarded to you and dpkong. :laugh: :laugh: :laugh: :thumbsup: :thumbsup:
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There is no way that the impulse time is 1x10^-7 s which is a microsecond. Not unless the watch is falling down at near the speed of light and rebounds at nearly the same speed.
http://www.atomicarchive.com/Fission/Fission8.shtml (http://www.atomicarchive.com/Fission/Fission8.shtml)
The complete process of a (nuclear) bomb explosion is about 80 times this number, or about a microsecond.
The original estimates is okay. No need to bring in impulse time unless you know for sure the watch rebounded. Also, the pressure rating means nothing when you discuss things like these, since basically pressure rating only takes into account water tightness (rubber seals, screw integrity etc.)
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Didn't know we have so many engineers and scientists on board :)
i'm still student ! :D
You are right Jeffrey!!! My calculation was flawed in that it only dealt with the force / pressure when the watch is say, resting on a surface, not the impact itself. Yes, it's the change in momentum or more precisely the rate of change of momentum =>
Rate of change = (mv-mu)/t
= m(v-u)/t
=ma
which is the applicable force!!!!
2013 Nobel prize in Physics jointly awarded to you and dpkong. :laugh: :laugh: :laugh: :thumbsup: :thumbsup:
Can some engineer kindly convert that to it's equivalent in beer and pasta??
:Laughing_on_floor:
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:o
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There is no way that the impulse time is 1x10^-7 s which is a microsecond. Not unless the watch is falling down at near the speed of light and rebounds at nearly the same speed.
http://www.atomicarchive.com/Fission/Fission8.shtml (http://www.atomicarchive.com/Fission/Fission8.shtml)
The complete process of a (nuclear) bomb explosion is about 80 times this number, or about a microsecond.
The original estimates is okay. No need to bring in impulse time unless you know for sure the watch rebounded. Also, the pressure rating means nothing when you discuss things like these, since basically pressure rating only takes into account water tightness (rubber seals, screw integrity etc.)
the impulse time is the time taken for the watch to change its momentum, it doesn't have anything to do with how fast the thing is falling, regardless the watch is travelling about the speed or light or as low as 1m/s , when it hits the floor, it still stops almost instantly. However, i do agree with you on the pressure rating but i use that as a reference only. :thumbsup:
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1 microsecond is 10-6 of a second. And as we get closer to the speed of light i.e 0.8c Newtonian physics fail and the world will behave as what was described by Einstein.
There is no way that the impulse time is 1x10^-7 s which is a microsecond. Not unless the watch is falling down at near the speed of light and rebounds at nearly the same speed.
http://www.atomicarchive.com/Fission/Fission8.shtml (http://www.atomicarchive.com/Fission/Fission8.shtml)
The complete process of a (nuclear) bomb explosion is about 80 times this number, or about a microsecond.
The original estimates is okay. No need to bring in impulse time unless you know for sure the watch rebounded. Also, the pressure rating means nothing when you discuss things like these, since basically pressure rating only takes into account water tightness (rubber seals, screw integrity etc.)
the impulse time is the time taken for the watch to change its momentum, it doesn't have anything to do with how fast the thing is falling, regardless the watch is travelling about the speed or light or as low as 1m/s , when it hits the floor, it still stops almost instantly. However, i do agree with you on the pressure rating but i use that as a reference only. :thumbsup:
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1 microsecond is 10-6 of a second. And as we get closer to the speed of light i.e 0.8c Newtonian physics fail and the world will behave as what was described by Einstein.
yes , true but that is not the speed of light, it is the time taken for the watch to decelerate. Its unit is not m/s . It never travels close to that fast. But it decelerated that fast, which has a unit of m/s2 .
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all wrong, the floor was this
(http://t7ak.roblox.com/2d141419dc3a56a37b56f6f414f39a86)