Question 1

Substance A has a density of 3 g/cm³ and substance B has a density of 4 g/cm³.In order to obtain equal masses of these two substances,what must be the ratio of the volume of A to the volume of B?

Accepted Answer

B

Question 2

A 10-kg piece of aluminum sits at the bottom of a lake,right next to a 10-kg piece of lead,which is much denser than aluminum.Which one has the greater buoyant force on it?

Accepted Answer

Buoyant force depends on the volume of the submerged object and the density of the fluid it is submerged in. Both aluminum and lead have the same volume (assuming they are both submerged to the same depth), but lead is much denser than aluminum. Therefore, lead will displace less water than aluminum, resulting in a smaller buoyant force acting on it. Therefore, aluminum will experience a greater buoyant force than lead.

Question 3

If atmospheric pressure increases by an amount Δp,which of the following statements about the pressure in a lake is true? (There could be more than one correct choice. )

Accepted Answer

C,E

Question 4

Salt water is denser than fresh water.A ship floats in both fresh water and salt water.Compared to the fresh water,the volume of water displaced in the salt water is

Accepted Answer

Since salt water is denser than fresh water, a ship will displace less volume of salt water to float because it needs to displace an amount of water equal to its own weight, not volume.

Question 5

The water pressure to an apartment is increased by the water company.The water enters the apartment through an entrance valve at the front of the apartment.Where will the increase in the static water pressure be greatest when no water is flowing in the system?

Accepted Answer

The increase in static water pressure will be the same at all faucets throughout the apartment when no water is flowing, as static pressure in a closed system does not depend on the distance from the source.

Question 6

An air bubble underwater has the same pressure as that of the surrounding water.As the air bubble rises toward the surface (and its temperature remains constant),the volume of the air bubble

Accepted Answer

As the air bubble rises toward the surface, the pressure decreases. According to Boyle's law, the volume of a gas is inversely proportional to its pressure when the temperature remains constant. Therefore, as the pressure decreases, the volume of the air bubble will increase.

Question 7

As shown in the figure,fluid fills a container having several sections.At which of the indicated points is the pressure greatest?

Accepted Answer

The answer of As shown in the figure,fluid fills a...

Question 8

When a heavy metal block is supported by a cylindrical vertical post of radius R,it exerts a force F on the post.If the diameter of the post is increased to 2R,what force does the block now exert on the post?

Accepted Answer

The answer of When a heavy metal block is supported...

Question 9

Salt water has greater density than fresh water.A boat floats in both fresh water and in salt water.Where is the buoyant force greater on the boat?

Accepted Answer

The buoyant force on an object is determined by the volume of fluid it displaces, not by the fluid's density. Since the boat displaces the same volume of water in both cases, the buoyant force remains the same.

Question 10

Consider a brick that is totally immersed in water,with the long edge of the brick vertical.The pressure on the brick is

Accepted Answer

The pressure in a fluid increases with depth due to the weight of the fluid above. Therefore, the pressure is greatest on the bottom of the brick, which is at the greatest depth.

Question 11

A boat loaded with rocks is floating in a swimming pool.If the rocks are thrown into the pool,the water level in the pool,after the rocks have settled to the bottom,

Accepted Answer

When the rocks are in the boat, they displace a volume of water equal to their weight. After being thrown into the pool, they displace water equal to their volume, which is less than the volume displaced by their weight. Therefore, the water level falls.

Question 12

A steel ball sinks in water but floats in a pool of mercury,which is much denser than water.Where is the buoyant force on the ball greater?

Accepted Answer

The buoyant force is equal to the weight of the fluid displaced by the object. Since mercury is much denser than water, the same volume of mercury displaced by the steel ball will have a greater weight than the same volume of water displaced. Therefore, the buoyant force on the ball will be greater when it is floating on the mercury.

Question 13

When a box rests on a round sheet of wood on the ground,it exerts an average pressure p on the wood.If the wood is replaced by a sheet that has half the diameter of the original piece,what is the new average pressure?

Accepted Answer

The answer of When a box rests on a round...

Question 14

A waiter fills your water glass with ice water (containing many ice cubes)such that the liquid water is perfectly level with the rim of the glass.As the ice melts,

Accepted Answer

The volume of ice is greater than the volume of the water it produces when melted, due to the lower density of ice compared to liquid water. However, the ice displaces its own weight in water while floating, so when it melts, it turns into the exact volume of water it had displaced, leaving the water level unchanged.

Question 15

A closed cubical chamber resting on the floor contains oil and a piston.If you push down on the piston hard enough to increase the pressure just below the piston by an amount Δp,which of the following statements is correct? (There could be more than one correct choice. )

Accepted Answer

The pressure in a fluid in a closed container is transmitted undiminished in all directions (Pascal's principle), so if the pressure just below the piston increases by Δp, the pressure everywhere in the oil will also increase by Δp, making choice A correct. Since the pressure increase is uniform throughout the oil, the force exerted by the oil on any surface in contact with it, including the top and bottom of the chamber, will increase equally if the areas are the same, making choice E correct as well.

Question 16

A wooden block contains some nails so that its density is exactly equal to that of water.If it is placed in a tank of water and released from rest when it is completely submerged,it will

Accepted Answer

Since the density of the wooden block is equal to that of water, it will not experience any buoyant force and hence will not rise to the surface or sink to the bottom. It will remain where it is released, in equilibrium with the surrounding water.

Question 17

A piece of iron rests on top of a piece of wood floating in a bathtub.If the iron is removed from the wood,and kept out of the water,what happens to the water level in the tub?

Accepted Answer

When the iron is on the wood, it causes the wood to displace more water than the wood would on its own, due to the added weight. When the iron is removed, the wood displaces less water, leading to a decrease in the water level.

Question 18

A hollow sphere of negligible mass and radius R is completely filled with a liquid so that its density is ρ.You now enlarge the sphere so its radius is 2R and completely fill it with the same liquid.What is the density of the enlarged sphere?

Accepted Answer

Since the original sphere is completely filled with liquid of density ρ, the mass of the liquid inside the sphere is given by:

M = ρ * V

where V is the volume of the sphere. Using the formula for the volume of a sphere, we have:

V = (4/3) * π * R^3

So the mass of the liquid in the original sphere is:

M = (4/3) * π * R^3 * ρ

When the sphere is enlarged, the volume is increased by a factor of 8 (since the radius is doubled). However, the mass of the liquid inside the sphere is still the same, so the density must be reduced by a factor of 8:

ρ' = ρ / 8

So the density of the enlarged sphere is ρ/8 or answer choice E.

Question 19

A styrofoam sphere of radius R has a density ρ.You now carefully compress the sphere so its radius is R/2.What is the density of the compressed sphere?

Accepted Answer

The answer of A styrofoam sphere of radius R has...

Question 20

A spherical ball of lead (density 11.3 g/cm³)is placed in a tub of mercury (density 13.6 g/cm³).Which answer best describes the result?

Accepted Answer

The lead ball will float because its density (11.3 g/cm³) is less than that of mercury (13.6 g/cm³). The percentage of the lead ball's volume that will be above the surface can be determined by the ratio of the difference in densities to the density of mercury, which is (13.6 - 11.3) / 13.6 ≈ 0.17, or 17%.

Quiz 15: Fluids

Substance A has a density of 3 g/cm³ and substance B has a density of 4 g/cm³.In order to obtain equal masses of these two substances,what must be the ratio of the volume of A to the volume of B?

A 10-kg piece of aluminum sits at the bottom of a lake,right next to a 10-kg piece of lead,which is much denser than aluminum.Which one has the greater buoyant force on it?

If atmospheric pressure increases by an amount Δp,which of the following statements about the pressure in a lake is true? (There could be more than one correct choice. )

Salt water is denser than fresh water.A ship floats in both fresh water and salt water.Compared to the fresh water,the volume of water displaced in the salt water is

The water pressure to an apartment is increased by the water company.The water enters the apartment through an entrance valve at the front of the apartment.Where will the increase in the static water pressure be greatest when no water is flowing in the system?

An air bubble underwater has the same pressure as that of the surrounding water.As the air bubble rises toward the surface (and its temperature remains constant) ,the volume of the air bubble

As shown in the figure,fluid fills a container having several sections.At which of the indicated points is the pressure greatest?

When a heavy metal block is supported by a cylindrical vertical post of radius R,it exerts a force F on the post.If the diameter of the post is increased to 2R,what force does the block now exert on the post?

Salt water has greater density than fresh water.A boat floats in both fresh water and in salt water.Where is the buoyant force greater on the boat?

Consider a brick that is totally immersed in water,with the long edge of the brick vertical.The pressure on the brick is

A boat loaded with rocks is floating in a swimming pool.If the rocks are thrown into the pool,the water level in the pool,after the rocks have settled to the bottom,

A steel ball sinks in water but floats in a pool of mercury,which is much denser than water.Where is the buoyant force on the ball greater?

When a box rests on a round sheet of wood on the ground,it exerts an average pressure p on the wood.If the wood is replaced by a sheet that has half the diameter of the original piece,what is the new average pressure?

A waiter fills your water glass with ice water (containing many ice cubes) such that the liquid water is perfectly level with the rim of the glass.As the ice melts,

A closed cubical chamber resting on the floor contains oil and a piston.If you push down on the piston hard enough to increase the pressure just below the piston by an amount Δp,which of the following statements is correct? (There could be more than one correct choice. )

A wooden block contains some nails so that its density is exactly equal to that of water.If it is placed in a tank of water and released from rest when it is completely submerged,it will

A piece of iron rests on top of a piece of wood floating in a bathtub.If the iron is removed from the wood,and kept out of the water,what happens to the water level in the tub?

A hollow sphere of negligible mass and radius R is completely filled with a liquid so that its density is ρ.You now enlarge the sphere so its radius is 2R and completely fill it with the same liquid.What is the density of the enlarged sphere?

A styrofoam sphere of radius R has a density ρ.You now carefully compress the sphere so its radius is R/2.What is the density of the compressed sphere?

A spherical ball of lead (density 11.3 g/cm³) is placed in a tub of mercury (density 13.6 g/cm³) .Which answer best describes the result?

Quiz 15: Fluids

Substance A has a density of 3 g/cm3 and substance B has a density of 4 g/cm3.In order to obtain equal masses of these two substances,what must be the ratio of the volume of A to the volume of B?

A 10-kg piece of aluminum sits at the bottom of a lake,right next to a 10-kg piece of lead,which is much denser than aluminum.Which one has the greater buoyant force on it?

If atmospheric pressure increases by an amount Δp,which of the following statements about the pressure in a lake is true? (There could be more than one correct choice. )

Salt water is denser than fresh water.A ship floats in both fresh water and salt water.Compared to the fresh water,the volume of water displaced in the salt water is

The water pressure to an apartment is increased by the water company.The water enters the apartment through an entrance valve at the front of the apartment.Where will the increase in the static water pressure be greatest when no water is flowing in the system?

An air bubble underwater has the same pressure as that of the surrounding water.As the air bubble rises toward the surface (and its temperature remains constant) ,the volume of the air bubble

As shown in the figure,fluid fills a container having several sections.At which of the indicated points is the pressure greatest?

When a heavy metal block is supported by a cylindrical vertical post of radius R,it exerts a force F on the post.If the diameter of the post is increased to 2R,what force does the block now exert on the post?

Salt water has greater density than fresh water.A boat floats in both fresh water and in salt water.Where is the buoyant force greater on the boat?

Consider a brick that is totally immersed in water,with the long edge of the brick vertical.The pressure on the brick is

A boat loaded with rocks is floating in a swimming pool.If the rocks are thrown into the pool,the water level in the pool,after the rocks have settled to the bottom,

A steel ball sinks in water but floats in a pool of mercury,which is much denser than water.Where is the buoyant force on the ball greater?

When a box rests on a round sheet of wood on the ground,it exerts an average pressure p on the wood.If the wood is replaced by a sheet that has half the diameter of the original piece,what is the new average pressure?

A waiter fills your water glass with ice water (containing many ice cubes) such that the liquid water is perfectly level with the rim of the glass.As the ice melts,

A closed cubical chamber resting on the floor contains oil and a piston.If you push down on the piston hard enough to increase the pressure just below the piston by an amount Δp,which of the following statements is correct? (There could be more than one correct choice. )

A wooden block contains some nails so that its density is exactly equal to that of water.If it is placed in a tank of water and released from rest when it is completely submerged,it will

A piece of iron rests on top of a piece of wood floating in a bathtub.If the iron is removed from the wood,and kept out of the water,what happens to the water level in the tub?

A hollow sphere of negligible mass and radius R is completely filled with a liquid so that its density is ρ.You now enlarge the sphere so its radius is 2R and completely fill it with the same liquid.What is the density of the enlarged sphere?

A styrofoam sphere of radius R has a density ρ.You now carefully compress the sphere so its radius is R/2.What is the density of the compressed sphere?

A spherical ball of lead (density 11.3 g/cm3) is placed in a tub of mercury (density 13.6 g/cm3) .Which answer best describes the result?

Substance A has a density of 3 g/cm³ and substance B has a density of 4 g/cm³.In order to obtain equal masses of these two substances,what must be the ratio of the volume of A to the volume of B?

A spherical ball of lead (density 11.3 g/cm³) is placed in a tub of mercury (density 13.6 g/cm³) .Which answer best describes the result?