when i hit a bottle with a stone it falls, why is that so? is that because of conservation of momentum?
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No because of Kinetic energy.\n\nLesson 1: Basic Terminology and Concepts\nKinetic Energy\nKinetic energy is the energy of motion. An object which has motion - whether it be vertical or horizontal motion - has kinetic energy. There are many forms of kinetic energy - vibrational (the energy due to vibrational motion), rotational (the energy due to rotational motion), and translational (the energy due to motion from one location to another). To keep matters simple, we will focus upon translational kinetic energy. The amount of translational kinetic energy (from here on, the phrase kinetic energy will refer to translational kinetic energy) which an object has depends upon two variables: the mass (m) of the object and the speed (v) of the object. The following equation is used to represent the kinetic energy (KE) of an object.
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Generally, some of their collective kinetic energy is converted into heat, so the KE after the collision is less than the initial KE.  Momentum is conserved.
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Wood floats in water becuase water is more dense (higher weight for the same volume) than wood. Boulders or rocks are much more dense than water so they sink. It isn't the total weight that's important but the density.
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Liquid drop is always taking a spherical shape because of the following  factors acting on it while falling freely.\n1) Gravitational force  acting on every molecule of the liquid.\n2)Atmospheric pressure acting  all around the surface of the drop.\n3)Inter- molecular attraction and bonding.\n4)Surface tension\nEXPLANATION.  \na)By gravitation liquid is freely falling, hence experience the weightlessness.In other words effect of gravitation is nullified due to free fall.\nb)Because  atmospheric pressure is acting all around the liquid mass, mass of the liquid is pushed towards the center of the mass.\nc)Inter-molecular forces are more in and around the center of the mass. Hence this also contributes something to become the falling  liquid mass to be spherical. \nd) Surface tension is also acting towards the center of the mass of the liquid.\nBy all the above reason falling liquid is spherical.\nNote- Falling liquid in large volume is not in spherical shape.
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It depends on how much water is displaced by the stone and log. The stone and log will be buoyed up by a force equal to the weight of the water displaced.
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The ball would bounce higher if the container kept a vacuum in it the entire time.  The first thing to understand is that there will not be pressure on top of the ball, there will be pretty much equal pressure around the ball from all sides; the air will spread evenly throught the container very rapidly.\n\nThis air will create drag, which will slow the descent of the ball and reduce the kinetic energy and momentum of the ball.  Drag and friction are called non-conservative forces, because when kinteic energy is lost to them, it is not transferred to another object, rather it is gone and not retrievable.  (It actually does get transferred, because no energy can truly be destroyed, but it is not retrieable.)\n\nSo what we have so far is a ball that is falling through dense air (greater pressure of a gas means a greater density of the gas), which is putting drag on the ball.  This means the ball does not fall as fast as it would in a vacuum, and the faster a rubber ball falls.  We then suck all the air out instantly, and the ball will bounce back up unrestricted by drag on its way up, but it would have bounced higher if it was not slwoed down by air during its fall and had a higher impact speed.
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((((((Edited)))))\n\nThe short answer is friction. If the drops were in a vacuum they would fall that the same rate no matter the size. The drag of the friction in the air slows down the falling drop.\nIts called fluid friction and is affected by viscosity of the air and the weight of the droplet overcoming the drag.\n\nhttp://www.answers.com/Fluid+Friction?gwp=12&method=2\n\nI dont know how helpful that was but do some searches on fluid friction and you may find what you are looking for\n\nGood Luck!
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youre holding a stone on a top of a hill (potential energy here) ---> you drop the stone off the hill (here kinetic energy) ---> the stone is on the ground (here again potential energy)
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B. Capillarity\n\n"Capillarity causes the part of the surface of a liquid in contact with a solid, to be either elevated above (e.g. water), or depressed below (e.g. mercury), the rest of the surface. This trait is named for the behaviour of liquids in capillary tubes placed perpendicular to the surface. The forces operating within capillarity are cohesion, adhesion, and surface tension.\n\nCapillary action helps us in our daily lives. For example, it makes water rise through the fibres of a kitchen towel. If capillary action did not exist, we would not be able to blot up spills on a table, or ink from a page."\n\n"Expert: Spaceman\nDate: 3/9/2006\nSubject: mechanics\n\nQuestion\nDear Spaceman, \n\nI have a son who is in high school who needs some help in mechanics,and I'm really not good in this area. Please help! \n\n1. In which of the following units is acceleration expressed? \n\nA. Newtons \nB. Foot-pounds \nC. Kilograms \nD. Meters per second squared \n\n\n2. A stone falls from a ledge and takes 8 seconds to hit the ground. The stone has an original velocity of 0 m/s. How tall is the ledge? \n\nA. 1,254.4 meters \nB. 313.6 meters \nC. 78.4 meters \nD. 39.2 meters \n\n\n3. A tank with a flat bottom is filled with water to a height of 4 meters. What is the pressure at any point at the bottom of the tank? (You can ignore atmospheric pressure when calculating your answer.) \n\nA. 4.0 kPa \nB. 9.8 kPa \nC. 18.9 kPa \nD. 39.2 kPa \n\n\n4. The ability of a material to transfer heat or electric current is called \n\nA. insulation. \nB. porosity. \nC. conductivity. \nD. convection. \n\n\n5. A steel block has a volume of 0.08 m³ and a density of 7,840 kg/m³. What is the force of gravity acting on the block (the weight) in water? \n\nA. 5,362.56 N \nB. 6,150.64 N \nC. 6,700.56 N \nD. 7,600.18 N \n\n\n6. When an automotive battery is fully charged, the sulfuric acid and water mixture will have a specific gravity of about \n\nA. 0.15. \nB. 1.0. \nC. 1.3. \nD. 2.5. \n\n\n7. If an object has a mass of 20 kg, what is the force of gravity acting on it on earth? \n\nA. 196 N \nB. 2.04 kg \nC. 32.67 N \nD. 1.96 kg \n\n\n8. If a small-diameter open glass tube is partially immersed in a vessel containing mercury, the surface of the mercury inside the tube will be \nA. lower than the mercury in the vessel, and shaped like the outside of an umbrella. \nB. higher than the mercury in the vessel, and shaped like the outside of an umbrella. \nC. lower than the mercury in the vessel, and shaped like the inside of a bowl. \nD. higher than the mercury in the vessel, and shaped like the inside of a bowl. \n\n\n9. How much time should be allowed for a 605-mile car trip if the car will be traveling at an average speed of 55 miles per hour? \n\nA. 8.75 hours \nB. 9 hours \nC. 10.5 hours \nD. 11 hours \n\n\n10. A machine is supplied energy at a rate of 4,000 W and does useful work at a rate of 3,760 W. What is the efficiency of the machine? \n\nA. 92 percent \nB. 94 percent \nC. 96 percent \nD. 97 percent \n\n\n11. What is the kinetic energy of an object that has a mass of 30 kilograms and moves with a velocity of 20 m/s? \n\nA. 2,940 J \nB. 5,880 J \nC. 6,000 J \nD. 12,000 J \n\n\n12. If a gas has a gage pressure of 156 kPa, its absolute pressure is approximately \n\nA. 56 kPa. \nB. 100 kPa \nC. 256 kPa. \nD. 300 kPa. \n\n13. According to Ptolemy's model of the movement of celestial bodies, \n\nA. the earth rotates around the sun. \nB. the sun is the center of the universe. \nC. the earth rotates around the moon. \nD. planets orbit in circular paths around the earth. \n\n\n14. A car with a mass of 1,200 kilograms is moving around a circular curve at a uniform velocity of 20 meters per second. The centripetal force on the car is 6,000 newtons. What is the radius of the curve? \n\nA. 160 meters \nB. 80 meters \nC. 32 meters \nD. 16 meters \n\n\n15. What force is required to accelerate a body with a mass of 15 kilograms at a rate of
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All the heaviest materials would be deposited first. When the force of the water falls, then the mass and weight of whatever material is being forced along with it will come into play. The heaviest of the dense material (like boulders) will be deposited first. Then whole trees (which because of their size tend to float better, but eventually the weight of them will be more than the force exerted on them). Then smaller rocks, etc, etc, etc, until you get down to light silt which would be the last particles to fall to the stream bottom.
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To answer the question asked:  It depends on neither.\n\nWeight is a factor of the amount of mass in a gravity field.  \n\nOn earth, the gravity field is uniform enough for weight to be a good measure of mass.  But take your 5 pound rock to the moon and it would weigh much less even though it still has the same mass.  It weighs less because the pull of gravity on the moon is less.  As the pull is what gives the rock its acceleration when dropped, it is only the pull that determines how fast something drops. \n\nThe last mission to the moon did the classical experiment of dropping a hammer and a feather at the same time.  Since there is no air on the moon they both dropped at the same rate.  But it was a rate that was much slower had the hammer been dropped on earth.\n\nSo it isn't the mass, nor an objects weight, but how strong the gravity field the object is in when it is dropped.\n\nThat means on earth all things fall at the same rate.  We see a difference when we drop a feather and a hammer on earth because of the friction of the air places greater drag on the feather than on the hammer.\n\nBut they are both pulled down at the same rate by the gravity of the earth.
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it's the same reason that if you mix oil and water in a glass, the oil will float to the top and the water will sink to the bottom.  oil has a lower density, which makes it lighter.  the heavier water gets pulled down by gravity and it displaces the oil.  since it is a liquid, the molecules of oil and water can move relative to each other.\n\nthe inside of the earth is a liquid, too - it is very hot and all but the outer surface of the earth is molten rock.  this has over time allowed the lighter minerals like quartz and feldspar to rise to the surface, while the heavier minerals like nickel and iron make up the earth's core.
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It has a minor specific gravity, or density.\n\nI came back, but I have seen that the Q has been answered. I want just to give another link and make more schematic the answer. \nThe link is : www.simetric.co.uk\nFor the rest : density = mass / volume\n         and : weight = mass * gravity\nCombining them, we obtain the following\n               weight = density * volume * gravity \nGravity, is a costant measure. So, if 2 liquids have the same volume and one of them has smaller density, is lighter than the other, because the weight is smaller.\nI use this schematic way in my pharmacy, when I try to explain something to my clients and (usually) it works.\nI hope that I was not boring.\n\nKaterina\n\nP.S. Why is not highlighted the link that I gave in my text, as in the following answer?
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It's bernoulli's principle. Fluids have a lower pressure when moving than when still. Since the water is moving past the spoons (which act like the wing of a plane) they feel a pull from the pressure drop and come together. Try it with a peice of paper sometime. Roll a piec of paper up so when you place it on a flat surface it looks like a curved bridge. then blow under it and it will collapse instead of blow away. It's pretty neet.
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The horse is transferring energy to the weight (i.e., doing work). Power is the rate at which the work is being done; power=energy/time. \n\nWhen the weight is released, potential is converted to kinetic energy. When the weight hits, the energy can go in a variety of ways:\n1) The noise of the impact carries away energy in the form of sound waves.  These quickly dissipate as heat.\n2) If something breaks, surface energy is created and dissipated as heat. You could consider this as the amount of work required to separate a solid object into pieces.\n3)If the floor flexes under the weight of the load, it stores energy  as a spring.\n4) Permanent deformations absorb energy as work done on the material and dissipate it as heat.\n5) there's probably more, but that should give you the general idea.
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The paper is out, because of wind resistance, leaving only the small and big rocks.  Refering to the 11th century-actually, Newton's law was supplanted some years ago, and we know that the acceleration due to gravity is determined by the combined gravitational forces of both objects.  Assuming an exactly equal shape and an exactly equal density of the two rocks, the larger would fall more rapidly, because of the involvement of it's own gravity.  If we assume, for example, that the small rock is the size of a baseball, and the big rock is the size of, oh...the moon, then the big rock will fall quite a bit faster (the combined gravity will be greater, because of greater mass).  As the large rock gets smaller, the gravity will decrease.  However, no matter how close in size the two rocks, there will be some difference.  It would not be easily measurable at anything less that a few million tons, but it would still be there.\nNewton was likely the greatest genius that ever lived...but we have moved beyond him in a lot of areas, including our understanding of gravity-
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Because if we sit down on it in the middle of the nite we fall in!!!  if you dont pick it up in the middle of the nite what happens? nothing other than we sit on droplets!!  its a no win.. except i hate to fall in lmao