if we put an iron ball in water,it sinks.but if an iron ship is put in water it floats!how?
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.
372889
Every body that is in a fluid, or it is floating on the surface, or is sunk to the bottom loses an equal ammount of weight as the weight of the displaced fluid by the volume of the body.\n\nThe force that makes body's float or makes them lighter in a fluid (for ex. water) is called Archimed's force or Archimed's principle.\nIf this force is grater then the weight of the body (G=m*g) then the body floats on the surface.\n\nArchimed's force is greater if the density of the fluid is bigger. Oil has the density of 900 g/cm3 and water has the density of 1000 g/cm3. Because the reason why the objects are floating in oil and in water is of same nature, floating on oil is similar to floating on water.\nBut water has a bigger push force then oil.
149451
Objects float because the density of the object is less than the density of the liquid. If you increase the density of water by dissolving something, such as sugar or salt, in it and create a situation where the density of the water exceeds the density of the egg, the egg will float.
429114
coz the principle of bouyancy comes into action. that is there is a space with air in the bottom part of the ship/boat n hence it doesnt allow it to sink.. n that too that a greater surface area is there so the pressure is distributed over a larger area. \n u can also call it Upthrust.\nexplanation-\nArchimedes discovered the law of bouyancy. It states: on everybody emersed in water (or fluid in general) there acts an upward force with magnitude equal to the wieght of displaced water/fluid.\n\nthere are 3 scenarios for a body in water:\n\n1. floats on the surface; gravity of the body equals bouyancy and equals exactly the amount of weight of the displaced water\n\n2. the body is entirely emersed in water; again gravity = bouyancy\n\n3. the body sank; gravity = boyancy + normal reaction of the floor.
39301
Think of it this way:  If an object weighs more than it would if it was made of water, it will sink.  If an object weighs less that it would if it was made of water it will float.\n\nA coin is made of solid metal which makes it denser than water, therefore heavier.  It will sink.  A ship is made of metal also, but NOT solid metal.  It also consists of other materials but mainly air (inside the ship).  This means it's lighter than water, which is why it will float.
567852
Both are floating because of differences in bouyance and density.\n\nThe hot air balloon floats because it is less dense than air making it bouyant. It will consequently rise into the air until the weight of the air it displaces is equal (density) is equal to that of the surrounding atmosphere, which is why balloons do not go flying off into space.\n\nA scuba diver has the same problem, but in reverse. As he goes deeper, the density of the water is increasing and pushes him or her back. Therefore, divers tend to sink to a specific depth unless they can increase their density. This is usually accomplished by bringing additional weight.
397031
Archimedes LAW of buoyancy states that any body completely or partially submerged in a fluid (gas or liquid) at rest is acted upon by an upward, or buoyant, force the magnitude of which is equal to the weight of the fluid displaced by the body.. also, the density of the ship( and the air inside it) is lesser than the density of water. \n\nBernoulli's principle explains why airplanes fly: air/water traveling at faster speed has lower pressure in it.\nthe shape of the airplanes wing is like half of a water drop. therefore the air flowing at the top/above the wing of an airplane is faster compare to the air underneath creating enough pressure to lift the airplane.
901405
nothing, the salt water will NOT react with iron, however the rion will just replace a few of the ions of the mineral and still probally nothing will happen
974729
Gravity. Water doesn't seek its own level on the Space Station, it forms a ball-shaped blob.
1102604
This is an oddly specific question just to be asked out of curiosity.\n\nThe mass of the cannon ball is 13.6 kg, thus it has a weight of about 133.4 Newtons (assume g = 9.81 m/s^2).\nThe force of weight is pointed down...however, since the cannon ball in not in a vacuum and/or not a point mass, it has a non-zero buoyant force acting upward on it.\n\nThe buoyancy force acting on the ball is dependent on the weight of the fluid (water in this case) it displaces.\nIron has a density of about 7874 kg/m^3, thus a 13.6 kg sphere would have a volume of about 1.73 E-3 m^3.\nIf we assume the salt water of the ocean has a uniform density of about 1028 kg/m^3, then the weight of the displaced water exerts a force of about 17.42 Newton’s upward.\n\nThus, the net force acting on (stationary) cannon ball is about 116 Newtons downward.\nAccording to Newton’s 2nd law,\nF = ma\nThis force will cause the 13.6 kg cannon ball to accelerate at a rate of 8.53 m/s^2.\n\nAssuming there is no "water" resistance / drag, then using the formula,\nd = 1/2 at^2,\nwhere the ball stars from rest and experiences a uniform acceleration for a time t as the ball covers d distance,\nThe cannon ball should take about 50.57 seconds to reach the bottom.\n\nHOWEVER,\nJust as there would be air friction if this ball was launched into the air, there is most defiantly "water" friction as this ball accelerated downward....eventually reaching a terminal velocity.\nThe water will exert a drag force upward on the ball, causing its acceleration to be non-uniform.\n\nThe drag force can be calculated as,\nF_d = C_d * ((p * v^2) / 2) * A\nwhere F_d is the drag force, C_d is the drag coefficient, p is the density of the medium which the ball is falling in, v is the instantaneous velocity of the ball, and A is the cross sectional surface area of the ball in the direction of travel.\nIn order to calculate the drag force, one must know the drag coefficient of the cannon ball in water, something which usually must be calculated experimentally.\nThe ball will accelerate non-uniformly until it reaches it terminal velocity in the water, at which time, acceleration will cease and the ball will continue falling at its terminal velocity.\n\nUnless more information is know (the drag coefficient), the best (guess)/estimate of the how long the ball will take is sometime longer than 50.57 seconds...probably on the order of well over a minute since the ball will not be accelerating nearly as long as it did in our mathematical model calculate earlier.
1122613
You must already understand the displacement description so here's an attempt to physically understand the process.\n\nGravity pulls everything with mass  towards the center of the Earth.  This includes water and even air.  This is what creates air pressure and water pressure within a column of the fluid.  The force towards the center of the Earth is called the Weight.  Weight is simply the mass of an object multiplied by the acceleration of gravity (32.2 feet per second).\n\nMolecules in fluids can move around very easily.  They are constantly being pulled downward by gravity.  Generally, they are blocked by other fluid molecules already below them but they pile up and apply a pressure to the poor suckers below them.  The molecules at the bottom of the stack are under tremendous pressure in very deep portions of the ocean because they have to support the weight of the molecules above them.  (This also creates a sea level air pressure of 14.7 pounds per square inch)\n\nShips weigh less than the water they displace.  Gravity is pulling that ship down, trying to get it to the center of the Earth.  Once the weight of the water equals the weight of the ship, the water pushes back with enough force to keep it afloat.  Water molecules can flow easily.  When they begin to weigh more than the effective weight of the ship, they will flow beneath it and push the ship upward.
630018
When you softly place a pin onto the surface of water (horizontally) it doesn't sink because the weight of the pin is balanced by the upward (vertical) component of surface tension. When you add a detergent powder it reduces the viscosity of water and hence the upward force due to vertical component of surface tenbsion decreases and hence it sinks.
67959
Oxygen in the atmosphere reacts with iron to oxidize it in what is called a redox reaction (oxidation/reduction).  The redox reaction is defined by the exchange of electrons--uncharged iron will lose two electrons to an oxygen molecule, creating iron oxide.  Water quicken rusting by serving as a catalyst.  Dissolved oxygen in the water reacts, and as the water dries, the oxygen becomes increasingly concentrated.\n\nShips will prevent wide-spread rusting by creating what is called a "sacrificial anode."  You might know the names anode and cathode from the ends of a battery.  Batteries function by employing two seperate redox reactions, where one end corrodes to release electrons, which travel to the other end and react with metal cations in solution, turning them to a solid metal.  In the case of ships, the corrosion of iron is prevented by creating a sacrificial anode out of something even more reactive than the iron (usually magnesium, if memory serves).  The corrosion of the magnesium releases excess electrons in the iron, which delays corrosion of the iron--oxyegn can grab the free electrons created by the corrosion of magnesium without needing to corrode the iron.\n\nI would imagine that the quickening of the rusting process cause by a scratch in the tin is due to the fact that the corrosion becomes concentrated in a single place.  The scratch likely serves as the "sacrificial anode" for the rest of the can.
770625
I'm sorry, i have to correct some of the misunderstandings posted above here.\n\nTHE WEIGHT DOES NOT, I REPEAT, DOES NOT CHANGE IN WATER.   weight is a term in physics for the interaction of gravitational forces on a masseous object.  Does the mass of the object change in water?  NO.  Does the mass of the earth change when an object enters water?  NO.  Therefore the weight is the same.\n\nWhy do objects feel lighter in water?  the difference in net force is the answer.  Weight still pulls down equally... However, the water creates a boyent force which counteracts a percentage of the weight (depending on the object submerged.  roughly counteracts 40% for humans, different for other objects).  In this way, while the weight is the same, the downward force of the object is less.  That's the confusion point for almost everyone who's answered so far.
257654
Say the anchor weighs 15 pounds in air and displaces 2 pounds of water.\nBefore the drop, the boat displaces its weight plus the 15 lb weight in air of the anchor. This is the maximum displacement situation, so the water is at maximum height.\nAfter the drop, if the anchor hits bottom, the boat displaces its weight only and the anchor displaces 2 lb of water, the minimum displacement situation, so the water is at minimum height.\nAfter the drop, if the anchor doesn't reach the bottom, the boat displaces its weight plus the 13 lb weight in water of the anchor. The anchor displaces 2 lb water. The total displacement is the same as the maximum displacement situation, so the water is at maximum height.
196335
A ship can float on water because the desity of the ship is less than that of the water arround it.  When I speak of the Density, I speak of the ship as a whole.  The materials can be much more dense than water including steel or even Concrete.  What matters is what is in the ship.  If there is mostly air or something light in the ship, the average desity of the ship is very low and the ship will float high in the water.  If there is a lot of heavy cargo, the ship will float low in the water, unless too much cargo is loaded that is too heavy, then the ship could actually sink.\nWhen the ship is sitting on the water, it is displacing a certain amount of water.  The surrounding water then places pressure upon the ship pushing inward and upward.  The ship, not weighing as much as the water that is displaced is held up by this pressure.  If the wieght of the ship becomes more than what is displaced, then the ship will sink.
973894
float as mercury has a density of about 13.6gm/cc and iron much lesser 7.85gm/cc. Mass is immaterial as  in a sufficient quantity of mercury even a 1000000000000kg iron ball will float