When a person sinks in the water, how long does it take for him/her to float back to the top,and why?
959415
Usually 23 to 24 hours.\nTakes that long for the gases in the body to build up enough to refloat.
1144254
Yes, with your lungs full of air you are bouyant, the problem comes when you have to take a breath.. most people let go of all the air and sink, the trick is just take little breaths while keeping most of your lungs full\n\nand also you need to have good balance, because to do what I said above you have to be on your back, and your feet are going to want to come down, but you have to balance them out with your body
605564
Water doesn't slow down gravity. Gravity always pulls things down at roughly 9.8 m/s^2 (at most places on Earth, anyway). What happened, though, is that the water slowed down the desent of the coins. Remember, water is a molecule. When gravity pulled the coins down through the water the water molecules pushed back up against the coins. Its Newton's law, "for every action there is an equal and opposite reaction." Air actually works the same way. Its called terminal velocity. If you jumped out of a plane you can only fall so fast before the force of the air molecules acting against gravity equals the downward force of gravity, thereby keeping you from accelerating downward to a faster speed.\n\nNow, as for why one hit sooner then the other, that's because of how they fell. If the coin fell flatwise on the water it falls slower because there is more surface area of the coin in the way of the water. If the coin falls on its edge there is less surface area of the coin to meet the opposing force of the water and, therefore, less resistance (although the coin will flop around and turn from the force more readily). Actually, predicting a coin's free movement through a liquid is quite difficult and involves a lot of fluid dynamics and center of mass stuff.\n\nFor short distances, though, you can generally fake a rough estimate by simplifying math. You know those things with a fishbowl and a shotglass that most places like Perkin's have? Where if you drop a quarter into the glass you get a free cookie or something? Most people drop the coin edgewise and then wonder why the coin misses. The best way to do it is drop the coin in flat over the glass because the force acting against the coin is more balanced and less prone to exerting a torque the the coin as it falls. Try it sometime and see for yourself.
518156
22 seconds.  I've beens swimming for about 8 years now.
702149
salt water is heavier than fresh water. If the water is salty enough, the egg will float. Otherwise, it will sink.
543600
well you have to make it to scuba training first.  you wont drown, your closely monitored and i believe your body naturally gives you about 4 mins. before you start to swallow water after blacking out. just don't panic that what kills most people in water.  oh yeah, its called shallow water blackout. you have to experience it so you know when its happening to you.
342841
It is different for every different circumstance. The key is when the force of gravity pulling you down is exactly equal to the drag on you from the rushing air, you arrive at terminal velocity. If you have a lot of drag (parachute deployed, a lot of loose clothing), it happens pretty quick. If you have low drag (tights, bald) then it takes longer.
695472
Okay,\n\nQuick method:\n\nShe picks up a certain K.E. (kinetic energy) before she hits the water and loses this K.E. 3m under. \n\nWe have KE = Force x distance = mad\n\nso we have m x a1 x d1 = m x a2 x d2\n\nm =65kg, a1= 9.8m/sec, d1=13m, d2= 3m\n\nF(ave)= m x a2= m x a1 x d1/d2 = 2760 1/3 N \n\nThe force exerted on her by the water from when she hits until she stops 3m under will not be constant but the average force stops her in a distance of 3m and has the above value
14540
I did some calculations a while back when I wanted to know how far away on the water a person standing in a rowboat could be seen. As best as I can remember, the top of his head would disappear from view at about 6 miles, given absolutely perfect viewing conditions, with no shimmering of heat waves etc from the waters surface or the surrounding air.
1132679
Maybe it has something to do with the actions you're making.  When you're timing yourself out of water, you're just sitting there right?  But when your under water, you're treding or moving in some sort?  Try timing yourself when your walking around the house or jumping up and down....the blood takes in more oxygen(which means you need more) when its pumping faster.  Just an idea!
722743
A person with increased muscle mass will tend sink.Those with a higher body fat percentage will tend to float.
508796
it depends on the situation and your physical condition at the certain time but on normal condition and circumstance, i'd say 2 - 3 minutes :-)
1043479
...because their density is less than water density (1000 Kg/m^3).\n\nIf the density of an object is less than the density of the water, it floats on the surface of the water. If the density of the object is equal to the density of the water, the object floats anywhere inside the water. If the density of the object is more than the density of the water, the object sinks to the bottom.
648278
a tab floats and stops the water
684710
A piece of iron has a density greater than water. Thus it will sink when the weight of the volume of water displaced by the piece of iron is less than the weight of the piece of iron. If iron is shaped, or used to make a ship,  the iron ship will float if the total volume of water displaced by the part of the ship in the water weighs more than the total weight of the iron used to make the iron ship. Thus, the upward force of buoyancy is greater than, or equal to,the downward force of gravity and the ship stays afloat.\n\nThis is called Archimedes's principle of buoyancy and it is fundamental to the design of all ships and heated air balloons.TWH
450269
Well if the ball is hollow then it will float. If the weight of the water displaced is greater than the weight of the object then it will float because the object is lighter then the area of water it is taking up.
868202
I float in a fresh water pool, don't you?  My head is not above water, but if my lungs are full of air I do not sink.  If I empty my lungs then I will sink.  What is your question?