why is it easier to lift a heavy stone under water?

Answer 1

Simple, because of the water pressure , which is under the stone, so once it is moved, it is lighter.

Answer 2

Due to buoyancy force.

Buoyancy is an upward force on an object immersed in a fluid (i.e., a liquid or a gas), enabling it to float or at least to appear lighter. Buoyancy is important for many vehicles such as boats, ships, balloons, and airships.

The weight of the displaced fluid is directly proportional to the volume of the displaced fluid (specifically if the surrounding fluid is of uniform density). Thus, among objects with equal masses, the one with greater volume has greater buoyancy.

Suppose a rock's weight is measured as 10 newtons when suspended by a string in a vacuum. Suppose that when the rock is lowered by the string into water, it displaces water of weight 3 newtons. The force it then exerts on the string from which it hangs will be 10 newtons minus the 3 newtons of buoyant force: 10 − 3 = 7 newtons.

Answer 3

because water does part of the job!

it is fairly to prove but i won't do it here, but basically when you put something in water (or any other liquid, or gas), the water exerts on that body an upwards force, which is equal to the weight of the water that would be contained in the volume of the object.

So basically, if you take an empty, closed, 1 quart bottle, and put it below water in a bath tub, the water will push it upwards with a force equal to the weight of one quart of water.

Of course, if the stone is less dense than water, then the force will be bigger than the weight of the stone, and it will float. This happens with pumice, full of air bubbles.

Answer 4

Enough measurements of weights like being supported by the water is done by the man. So the water is support the stone.

Answer 5

The water is contributing a boyant force up on the object. The boyant force is equal to the volume of the object times the density of the water times gravitational constant. Essentially the water is pushing up on the object. This boyant force can be more clearly seen on object that floats. The reason that an object floats is that the boyant force due to water or watever liquid it its floating on is greater than its weight.

Answer 6

because of bouyancy

bouyancy is what makes some things float, but even things that sink are pushed up by the displaced water, they just aren't pushed hard enough to make them float

for something to go under water, it has to push aside the amount of water that is taken up by its volume

it you put something exacly the weight of water in the water, it has what is called "neutral" bouyancy, it neither wants to float or sink because the push of the displaced water is equal to the weight of the something

if the something is less dense than water, it cannot push enough water aside to sink all the way into the water

if it is more dense than water it can push aside the water

if you put something in the water that is twice as dense as water, it will sink, but you will be able to lift if as though it weighed only half as much (until any part of it comes out of the water)

Answer 7

Boyancy, even though some things may not float, they still have some boyancy in water, so to pick up something in water all you have to do is over come the excess mass preventing the item from being boyant.

Answer 8

its becoz of buoyant force i.e. the upward force exerted by water or any fluid.as the weight i.e. the gravitational force determines haeviness which acts downwards so if an upward force acts on the same object then the net force acting on it reduces so the weight reduces and hence it becomes lighter.

Answer 9

the weight of any submerged object is decreased by the weight of the water displaced. Water weighs 62.43 #/ft^3 or 1Mg/m^3.
if you know the density of the rock.

Answer 10

Archimedes principle