Damage Definition and 130 Threads

I'm interested in understanding what effect does long-term radiation and microdust exposure would do to the surface roughness of a high-precision mirror like the one on the Hubble. Since it has been on orbit for 24 years, it provides an unique opportunity to estimate accumulated environmental...

Note: My english isn't well. Everyone knows toothpaste's has chemicals in variety. Floride is the main chemical. But how do you know if its not harm your health in the future? May be it cause cancer in the future. So what precautions do you take when you brush your teeths? How long have you...

This is a very basic electronics question, so I hope this is an appropriate forum. When an electronic device is plugged into a power strip, does it make any difference to the device whether it is unplugged and re-plugged from the power strip or if the power strip is switched on or off. I...

Shift workers beware: Sleep loss may cause brain damage, new research says http://www.cnn.com/2014/03/19/health/sleep-loss-brain-damage/index.html?hpt=hp_t2

http://www.nytimes.com/2013/12/22/us/spike-in-harm-to-liver-is-tied-to-dietary-aids.html I'm aware that excessive vitamins can cause liver damage. Too much Vitamin D can be harmful to the liver.

How long would it take for your brain to be permanently damaged after holding your breath? In other words, after how long of holding your breath will your brain function be at risk? A quick Google search gave me varied results. :confused:

Brain damage, good and bad "damage" There have been cases where normal people without any sort of brain malfunction have lived their lives totally fine without any problem for 20+ years and then they have an accident involving head injury, wake up from either a coma or just after a very good...

A tiny pellet thrown by hand would never harm a glass window , but fire that pellet from a shotgun and it will shatter the glass into pieces , obviously the speed of the pellet made all the difference here .. how could this be explained on the actual atomic level (I understand the theoretical...

It is available on a freetrial use. WARNING: DO NOT USE IT! After I used it I found that bookmarks and autofills on my browser (Avant) were completely screwed up. Fortunately my computer does weekly backups, so I was able to restore the items.

Is it possible to damage the continuity tester if the leads are hooked to a battery? For a clamp on AC amp meter; Is it possible to damage the sensor if put around a DC hot wire in a circuit? I am so surprised it is difficult to find events of people damaging their meters. God knows the...

This is the MM I am using : http://www.sears.com/shc/s/p_10153_12605_03482139000P I made a little electric motor powered by 1.5 volts. However, like the newbie I am, I thought you could measure R on a live setup. Of course the reading was probably wrong, but could this have damaged my meter...

I recently got a concussion from playing hockey- I think it's time for a new helmet. I was looking at a new-ish helmet that claims to have superior protection than the others but a video promo for it was sort of unsettling for me:http://www.youtube.com/watch?v=yAV99h1Aeg0e. At around 3:00 it...

I have a weird question that I can't figure out where to start. It's been a while since physics: A wind mill has a hub and 3 blades the hub weights 45000 lbs and each blade weighs 14000 lbs. the CG is at the hub when the assembly is intact. We had a storm and 2 of the 3 blades broke so...

I'm working on a unlimited time final exam. There is a problem that I have been thinking about for the last three days but I still couldn't get it. It is worth about 15% of the final and the final is 35% of my grade. I could work on the final for another 5 days before I turn it in. Now the...

what does more damage an object w/ a high acceleration or a greater momentum i was watching one of my favorite tv shows "Justified" and i started to wonder would a bullet moving at a greater acceleration hence greater force (F=ma) inflict more damage or would a bullet w/ a greater velocity...

My phone (LG 900something) takes several hours to charge when plugged into my USB port (with a cable that came with the phone). But it only takes an hour to charge using a 3rd party charger plugged into the cig lighter of my car (charger is meant for phones, but its got, like, 10 tips). I can...

Hi, This week I was in an accident - one track road head on round a bend. My impression was that the other car was faster and yet their car was more damaged. I know that make and design is a huge issue in this but trying to recall my physics and failing. In the not real, frictonless...

I'm trying to charge my cellphone and would like to know how many volts would cause the cellphone battery damage? Also, how many amps would an average phone need to be charged?

The ribosomes have a membrane to prevent damage of the cell from the enzyme. but why are the cells not damaged when the enzymes are digesting unwanted structures, since the enzymes have to be released to digest unwanted structures.

I want to know what is happening at micro-level, how macroscopic tumbling of the solution can actually break a chemical bond?

Homework Statement A wrecking ball is commonly used to destroy old buildings. The energy comes from a motor pulling a large pendulum back, which then allows it to swing against a wall. Why not just use the motor to do the same work on the wall? 2. The attempt at a solution The kinetic...

i want to make a 5v dc power supply for microcontroller i know how to make it i am going to use a 220v to 15v transformer and then by using capacitor and 7805 regulator ic i will convert it to 5v my question is as in transformer pout=pinput (ideally) by decresing the voltage from 220 to 15...

I was astonished recently to find myself able to look directly into the sun without experiencing impairment of vision as a result. I have done so many times since but there are occasions when the light is too bright. What I saw when I looked at the sun was quite awe inspiring. The outer rim...

Let's say you are given a choice of being hit by one of two objects, both going at 50 miles Per hour ( about 80 Km per hour). One is a ten pound (3.5 kg) traffic cone made of rubber. The other is a standard baseball which weighs at around 5oz, which is less than half a pound or about a fifth of...

http://en.wikipedia.org/wiki/Near-Earth_supernova So we know that many people are putting hard constraints on the galactic habitability zone based on the presence of nearby supernova/gamma ray bursts. But if they *only* affect the ozone layer, then I doubt that it's as hard of a constraint as...

This is what FEMA calls "Insufficient Damage" i can't see that this is anything other than a co-ordinated effort to reject legitimate claims. I've spent many hours in Pleasant Grove and Concord, and this is the typical type of destruction there for as far as the eye can see in either...

My specific question is can the magnets in an Ashton BA15 40W bass amp damage the HDD in a laptop (we have a Samsung about a year and a quarter old and an Acer about a year old). I've read the following threads: https://www.physicsforums.com/showthread.php?t=411895&highlight=magnet...

The following excerpt is taken from a Swiss Federal Nuclear Safety Inspectorate (HSK) publication[1]: “In the year 1988 a large scale crash test was performed at the US Sandia National Laboratory in which a Phantom military jet with a weight of 19 tons was impacted at a velocity of 774 km/h...

It is often said that each nuclear plant is only designed to handle up to a certain rated earthquake intensity -- but I would like to know if they are designed to degrade gracefully if they are subjected to larger earthquakes? It is certainly possible to make some guesses regarding the...

Question about Gamma Radiation. I understand that Gamma Radiation, like X-Rays, are just photons (light particles) at different frequencies. I was reading an article about the Nuclear Plant problems in Japan, and the article stated that photons from Gamma Radiation for the most part pass...

So I want to be a physicist. Avoiding false modesty, I'm pretty good at it, probably the best in my year in physics and possibly math. I never have problems learning, unless the material is shallowly presented and I reject it, which has happened in many of my classes, unfortunately. I've taken...

If two cars of equal size were each traveling 50mph and hit each other in a head-on collision would the damage sustained best resemble hitting a brick wall at 50mph or 100mph? Assume the full impact of the head-on collision was into each car and not vectoring away from the impact zone.

I know this is a low level math course, but will it screw up my chances for grad school admissions? I plan to apply for grad school in either math, statistics, or economics (not entirely sure yet). I'm especially pissed by this because I knew the material inside and out, aced every quiz...

If an average adult male fell from a bridge (ex. golden gate) what would be the impact on his body when he hit still water versus water with waves. What is his acceleration, momentum, and his change of momentum when he hits the water With these in mind how does the fall affect his organs...

Hi Guys, I understand that the energy associated with wind damage from a hurricane goes as the third power of the velocity of the wind. How is this relationship derived? I ask because when I think of wind energy, I think of Kinetic Energy going as the square of the velocity...

Now my doctor is thinking my previous laparoscopic nissen fundoplication damaged my vagus nerve. This wasn't on the list of potential surgical problems I was given. I'm reading about it and it seems that damage from the surgery is now considered rather common? It's not like I had much...

I think I read a post on this forum about the lack of pictures of damage from the BP oil spill. I found this site today and wanted to share it. Edit by Evo: Sorry, that's not an approriate link. It contains misinformation worded to create fear mongering.

How do you feel that BP should be punished?

Chest x-ray? Not my first post, but had to create another username as I forgot my password and apparently there are not 7 letters in the word "physics"...? Anyway, I have smoked about 1/2 pack of cigs a day for about 18 months now. I really regret this, as it was stupid. Will an ordinary...

Greetings, I am new in this forum, but I have a question about Plasma televisions. I was told that they have an adverse effect on eyesight. Can anyone elaborate? I tried looking on www.altavista.com for Journals and Information on the medical aspect, but there is nothing but...

I've got a bit of a painful question. I'm looking at several different articles that mention radiation damage to DNA quantitatively, but they use vastly different ways of representing this damage. So my question is, is it possible, first of all, to convert between umol/J (micromoles per...

http://www.nature.com/nature/journal/v446/n7138/abs/nature05631.html Very interesting article. I'm not proud of being an utilitarian anymore.

Homework Statement I don't know if this one belongs to something like the mythbusters, because of the complexity it needs for the actual testing. This is the situation: in my country every week somebody gets hurt because of stray bullets, This is provoked by irresponsible people who tend to...

I feel a little silly for posting this rather mundane question- but I really am at then end of my (limited) wits. I have an iPhone, and there is a rather strong magnet on my favorite purse (I believe it is a neodymium magnet, but don't know for sure). I have been researching this issue online...

Somebody tells you that a single ultraviolet photon carries an energy equivalent of about 10 electron volts (eV, see Appendix B). You propose a damage mechanism: A photon delivers that energy into a volume the size of the cell nucleus and heats it up; then the increased thermal motion knocks...

Hello, I was wondering if someone could clarify the major differences and limitations of Damage Mechanics and Fracture Mechanics. I'm more familiar with the fracture mechanics approach, but have never done any damage mechanics before. I'm just trying to sort out in my head how fracture...

Hello PF. I'm building a circuit that uses triacs to switch power on and off for a series of devices. However my teacher warned me that Triacs basically skip the zero part of the waveform, and that can affect digital devices, such as my computer. I'm looking for a more in-depth explaniation...

I use to box in the amateurs (my last fight was April 5th). I stopped boxing due to losing motivation, getting bored, etc, but I've missed it a lot over the past few months and am thinking of getting back into it. I don't plan to go pro or anything. Also, I will be starting university for math...

What damage to the body can infrared rays, radar waves, FM waves, TV waves, "shortwav What damage to the body can infrared rays, radar waves, FM waves, TV waves, "shortwave" waves, and AM waves do? I have to do a physics project on causes of cancer, based on a physics standpoint. I have an...

Hello all, I am a member over at the James Randi Educational Foundation (JREF) forum, and we've been having a rather lively discussion regarding the conditions under which transient voltages can damage EEPROM. This discussion can be found here...