Tag: applications of floatation

Questions Related to applications of floatation

A cube of size 10 cm is floating in equilibrium in a tank of water. When a mass of 10 gm is placed on the cube, the depth of cube inside water increases by $\mathrm { g } = 10 \mathrm { m } / \mathrm { s } ^ { 2 }$ density of water $= 1000 \mathrm { kg } / \mathrm { m } ^ { 3 } )$

physics upthrust in fluids, archimedes' principle and floatation applications of floatation principle of floatation and its applications when do objects float on water?

  1. 0.1 m

  2. 1 mm

  3. 1 m

  4. 0.31 m

Show answer
Correct Option: B
Explanation:

Let $x$ be the initial depth upto which the cube is sinked in water.

Let $d$ be the density of the cube
Then
$x\times 10 \times 10\times 1 \times g$
$=10\times 10 \times 10\times 1 \times g\times d$........(1) 
$\Rightarrow x=10d$
Let $x^1$ be the new depth, then 
$x^1\times 100 \times g=1000\times d \times g+10g$........(2)
subtracting (1) and (2) we get
$\Rightarrow 100x^1=10x+10$
$x^2-x= \frac{1}{10cm}=1mm$
Hence,
option $B$ is correct answer.

A hydrogen balloon released on the moon would:

physics upthrust in fluids, archimedes' principle and floatation applications of floatation principle of floatation and its applications when do objects float on water?

  1. climb up with an acceleration of $9.8 \ m/s^2$

  2. climb up with an acceleration of $9.8 \times 6 \ m/s^2$

  3. neither climb nor fall

  4. fall with an acceleration of $9.8/6 \ m/s^2$

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Correct Option: D
Explanation:

As there is no atmosphere on the surface of the moon  so no bouyancy will act Hence it will fall with acceleration $9.8/6 m/s^2$

Statement I:- A block is immersed in a liquid inside a beaker,which is falling freely. Buoyant force acting on block is zero.
Statement II:- In case of freely falling liquid there is no pressure difference between any two points.

physics upthrust in fluids, archimedes' principle and floatation applications of floatation principle of floatation and its applications when do objects float on water?

  1. Statement I is true,statement II is true and statement II is a correct explanation for statement I.

  2. Statement I is true,Statement II is true and statement II is NOT the correct explanation for statement I.

  3. Statement I is true,Statement II is false.

  4. Statement I is false,Statement II is true.

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Correct Option: A

Ice floats on the surface of water because its density is ______ that of water.

physics upthrust in fluids, archimedes' principle and floatation applications of floatation principle of floatation and its applications when do objects float on water?

  1. more than

  2. less than

  3. same as

  4. cant say

Show answer
Correct Option: B
Explanation:

TRUE
Ice floats in water because it is less dense than water. So any substance that has a lower density in its solid state than in its liquid state will float.

A block of wood floats in water with two-third of its volume submerged. Find the density of wood. Density of water is $10^3\ kg/m^3.$

physics upthrust in fluids, archimedes' principle and floatation applications of floatation principle of floatation and its applications when do objects float on water?

  1. 0.67

  2. 0.76

  3. 0.82

  4. 0.28

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Correct Option: A

A body of density $\rho$ sinks in a liquid of denisty $\rho _L$. The densities $\rho$ and $\rho _L$ are related as:

physics upthrust in fluids, archimedes' principle and floatation applications of floatation principle of floatation and its applications when do objects float on water?

  1. $\rho = \rho _L$

  2. $\rho < \rho _L$

  3. $\rho > \rho _L$

  4. nothing can be said

Show answer
Correct Option: C
Explanation:

According to archimedes principle a body floats in a fluid if the density of the body is less than that of the fluid.
If the density of body is greater than that of fluid, it will sink.
In the above case, Since the body has  a higher density, therefore it will sink.

The hot air balloon rises because it has a gas that is

physics upthrust in fluids, archimedes' principle and floatation applications of floatation principle of floatation and its applications when do objects float on water?

  1. denser than air

  2. less dense than air

  3. equally dense as air

  4. the given statement is wrong

Show answer
Correct Option: B
Explanation:

Hot air balloon has hot air inside.  Also hot air is less dense than cooler air which surrounds the hot air balloon. This means hot air is lighter than equal volume of cold air.  Hence due to buoyant force of cold air, the balloon rises.

If a piece of ice floating on the surface of water in a beaker melts completely, the level of water

physics upthrust in fluids, archimedes' principle and floatation applications of floatation principle of floatation and its applications when do objects float on water?

  1. Rises

  2. Remains the same

  3. Falls

  4. Initially rises and then falls

Show answer
Correct Option: B
Explanation:

When a piece of ice is placed in a beaker containing water, some of its portion remains out of the water level. Since the volume of ice is greater than the water hence after melting the volume of the piece will decrease and the water level will remain the same.

State whether true or false:

Ice is less dense than water (because it has more volume for the same mass), which is why ice floats on water.

physics upthrust in fluids, archimedes' principle and floatation applications of floatation principle of floatation and its applications when do objects float on water?

  1. True

  2. False

Show answer
Correct Option: A
Explanation:

Answer is A.

As water is cooled down, however, the molecules have less energy and hydrogen bonding takes over. The molecules form a ordered crystal through hydrogen bonding that spaces the molecules farther apart than when they were in a liquid. This makes ice less dense than water allowing it to float.
Hence, the statement is true.

What can you say about the average density of a ship floating on water in relation to the density of water?

physics upthrust in fluids, archimedes' principle and floatation applications of floatation principle of floatation and its applications when do objects float on water?

  1. Average density of ship is more than the density of water.

  2. Average density of ship is less than the density of water.

  3. Average density of ship is equal to the density of water.

  4. None of the above

Show answer
Correct Option: B
Explanation:

Average density of ship is less than the density of water.

It is important to realize that, while they are related to it, the principle of flotation and the concept that a submerged object displaces a volume of fluid equal to its own volume are not Archimedes' principle. Archimedes' principle, as stated above, equates the buoyant force to the weight of the fluid displaced.
So, according to law of flotation, a body will float in a fluid if it has less density than the fluid.
So, in order for the ship to float, its average density must be less than the water.