Question 1

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

A) rise to the surface. 
B) sink to the bottom. 
C) remain where it is released.

Question 2

A 4.7-kg solid sphere,made of metal whose density is 4,000 kg/ m3. hangs by a light cord.When the sphere is immersed in water,what is the tension in the cord? The density of water is 1000 kg/m3.

Accepted Answer

A) 35 N 
B) 40 N 
C) 46 N 
D) 52 N 
E) 58 N

Question 3

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

A) increases. 
B) decreases. 
C) remains constant. 
D) increases or decreases,depending on the rate it rises.

Question 4

The density of material at the center of a neutron star is approximately 1.00 × 1018 kg/m3.What is the mass of a cube of this material that is 
On each side.(One micron is equal to 1.00 × 10-6 m. )

Accepted Answer

A) 5.45 kg 
B) 4.74 kg 
C) 6.16 kg 
D) 6.70 kg

Question 5

What force does the water exert (in addition to that due to atmospheric pressure)on a submarine window of radius 44.0 cm at a depth of 9,400 m in sea water? The density of sea water is 1025 kg/m3.

Accepted Answer

A) 5.74 × 107 N  
B) 5.74 × 1011 N 
C) 2.87 × 1011 N 
D) 1.83 × 107 N 
E) 2.87 × 107 N

Question 6

Water flows out of a large reservoir through an open pipe,as shown in the figure.What is the speed of the water as it comes out of the pipe?

Accepted Answer

A) 8.9 m/s 
B) 9.9 m/s 
C) 13 m/s 
D) 14 m/s 
E) 16 m/s

Question 7

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

A)   =
 
B)   =
 
C)   =
 
D)   =
 
E)   =

Question 8

Ideal incompressible fluid flows through a 4.0-cm-diameter pipe at 1.0 m/s.There is a 2.0 cm diameter constriction in the line.What is the speed of the fluid in this constriction?

Accepted Answer

A) 0.25 m/s 
B) 0.50 m/s 
C) 2.0 m/s 
D) 4.0 m/s

Question 9

Water flows through a pipe.The diameter of the pipe at point B is larger than at point A.Where is the water pressure greatest?

Accepted Answer

A) at point A 
B) at point B 
C) It is the same at both A and B.

Question 10

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

A) at a faucet close to the entrance valve 
B) at a faucet far from the entrance valve 
C) It will be the same at all faucets. 
D) There will be no increase in the pressure at the faucets.

Question 11

A 12,000-N car is raised using a hydraulic lift,which consists of a U-tube with arms of unequal areas,filled with oil with a density of 800 kg/m3 and capped at both ends with tight-fitting pistons.The wider arm of the U-tube has a radius of 18.0 cm and the narrower arm has a radius of 5.00 cm.The car rests on the piston on the wider arm of the U-tube.The pistons are initially at the same level.What is the force that must be applied to the smaller piston in order to lift the car after it has been raised 1.20 m? For purposes of this problem,neglect the weight of the pistons.

Accepted Answer

A) 0.954 kN 
B) 1.88 kN 
C) 1.96 kN 
D) 3.67 kN 
E) 1.20 kN

Question 12

A crane lifts a steel submarine of density 7800 kg/m3 and mass 20,000 kg.What is the tension in the lifting cable (a)when the submarine is submerged in water of density 1000 kg/m3,and (b)when it is entirely out of the water?

Accepted Answer

A) (a)2.0 × 105 N (b)1.7 × 105 N 
B) (a)1.7 × 105 N (b)2.0 × 105 N 
C) (a)2.6 × 103 N (b)2.0 × 105 N 
D) (a)2.0 × 105 N (b)2.6 × 103 N

Question 13

A 200-kg flat-bottomed boat floats in fresh water,which has a density of 1000 kg/m3.If the base of the boat is 1.42 m wide and 4.53 m long,to what depth is the bottom of the boat submerged when it carries three passengers whose total mass is 257kg?

Accepted Answer

A) 7.10 cm 
B) 7.53 cm 
C) 7.95 cm 
D) 8.52 cm

Question 14

A rectangular wooden block measures 10.0 cm × 4.00 cm × 2.00 cm.When the block is placed in water,it floats horizontally,with its bottom face 1.65 cm below the surface.What is the density of the wood? The density of water is 1.00 g/cm3.

Accepted Answer

A) 0.825 g/cm3 
B) 1.21 g/cm3 
C) 1.65 g/cm3 
D) 0.606 g/cm3 
E) 0.350 g/cm3

Question 15

When a container of water is placed on a laboratory scale,the scale reads 120 g.Now a 20-g piece of copper (of density 8.9 g/cm3)is suspended from a thread and lowered into the water,not touching the bottom of the container.What will the scale now read? The density of water is 1.0 g/cm3.

Accepted Answer

A) 120 g 
B) 122 g 
C) 138 g 
D) 140 g

Question 16

Water,which we can treat as ideal and incompressible,flows at 12 m/s in a horizontal pipe with a pressure of 3.0 × 104 Pa.If the pipe widens to twice its original radius,what is the pressure in the wider section?

Accepted Answer

A) 3.0 × 104 Pa 
B) 4.9 × 104 Pa 
C) 7.4 × 104 Pa 
D) 9.8 × 104 Pa

Question 17

As a rock sinks deeper and deeper into water of constant density,what happens to the buoyant force on it if it started above the surface of the water?

Accepted Answer

A) The buoyant force keeps increasing steadily. 
B) The buoyant force remains constant. 
C) The buoyant force first increases and then remains constant. 
D) The buoyant force steadily decreases.

Question 18

A circular window 30 cm in diameter in a submarine can withstand a net maximum force of 5.20 × 105 N without damage.What is the maximum depth in a fresh-water lake to which the submarine can go without damaging the window? The density of fresh water is 1000 kg/m3.

Accepted Answer

A) 680 m 
B) 740 m 
C) 1200 m 
D) 750 m

Question 19

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

A) floating on the mercury 
B) submerged in the water 
C) It is the same in both cases. 
D) It cannot be determined from the information given.

Question 20

A round coin has a diameter of 19.55 mm,a thickness of 1.55 mm,and a mass of 2.50 g.What is its density?

Accepted Answer

A) 5.37 × 103 kg/m3 
B) 21.5 × 103 kg/m3 
C) 1.34 × 103 kg/m3 
D) 2.68 × 103 kg/m3 
E) 1.86 × 10-4 kg/m3

Exam 15: Fluids

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 4.7-kg solid sphere,made of metal whose density is 4,000 kg/ m³. hangs by a light cord.When the sphere is immersed in water,what is the tension in the cord? The density of water is 1000 kg/m³.

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

The density of material at the center of a neutron star is approximately 1.00 × 10¹⁸ kg/m³.What is the mass of a cube of this material that is On each side.(One micron is equal to 1.00 × 10^-6 m. )

What force does the water exert (in addition to that due to atmospheric pressure) on a submarine window of radius 44.0 cm at a depth of 9,400 m in sea water? The density of sea water is 1025 kg/m³.

Water flows out of a large reservoir through an open pipe,as shown in the figure.What is the speed of the water as it comes out of the pipe?

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?

Ideal incompressible fluid flows through a 4.0-cm-diameter pipe at 1.0 m/s.There is a 2.0 cm diameter constriction in the line.What is the speed of the fluid in this constriction?

Water flows through a pipe.The diameter of the pipe at point B is larger than at point A.Where is the water pressure greatest?

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?

A crane lifts a steel submarine of density 7800 kg/m³ and mass 20,000 kg.What is the tension in the lifting cable (a) when the submarine is submerged in water of density 1000 kg/m³,and (b) when it is entirely out of the water?

A 200-kg flat-bottomed boat floats in fresh water,which has a density of 1000 kg/m³.If the base of the boat is 1.42 m wide and 4.53 m long,to what depth is the bottom of the boat submerged when it carries three passengers whose total mass is 257kg?

A rectangular wooden block measures 10.0 cm × 4.00 cm × 2.00 cm.When the block is placed in water,it floats horizontally,with its bottom face 1.65 cm below the surface.What is the density of the wood? The density of water is 1.00 g/cm³.

When a container of water is placed on a laboratory scale,the scale reads 120 g.Now a 20-g piece of copper (of density 8.9 g/cm³) is suspended from a thread and lowered into the water,not touching the bottom of the container.What will the scale now read? The density of water is 1.0 g/cm³.

Water,which we can treat as ideal and incompressible,flows at 12 m/s in a horizontal pipe with a pressure of 3.0 × 10⁴ Pa.If the pipe widens to twice its original radius,what is the pressure in the wider section?

As a rock sinks deeper and deeper into water of constant density,what happens to the buoyant force on it if it started above the surface of the water?

A circular window 30 cm in diameter in a submarine can withstand a net maximum force of 5.20 × 10⁵ N without damage.What is the maximum depth in a fresh-water lake to which the submarine can go without damaging the window? The density of fresh water is 1000 kg/m³.

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?

A round coin has a diameter of 19.55 mm,a thickness of 1.55 mm,and a mass of 2.50 g.What is its density?

Exam 15: Fluids

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 4.7-kg solid sphere,made of metal whose density is 4,000 kg/ m3. hangs by a light cord.When the sphere is immersed in water,what is the tension in the cord? The density of water is 1000 kg/m3.

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

The density of material at the center of a neutron star is approximately 1.00 × 1018 kg/m3.What is the mass of a cube of this material that is On each side.(One micron is equal to 1.00 × 10-6 m. )

What force does the water exert (in addition to that due to atmospheric pressure) on a submarine window of radius 44.0 cm at a depth of 9,400 m in sea water? The density of sea water is 1025 kg/m3.

Water flows out of a large reservoir through an open pipe,as shown in the figure.What is the speed of the water as it comes out of the pipe?

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?

Ideal incompressible fluid flows through a 4.0-cm-diameter pipe at 1.0 m/s.There is a 2.0 cm diameter constriction in the line.What is the speed of the fluid in this constriction?

Water flows through a pipe.The diameter of the pipe at point B is larger than at point A.Where is the water pressure greatest?

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?

A crane lifts a steel submarine of density 7800 kg/m3 and mass 20,000 kg.What is the tension in the lifting cable (a) when the submarine is submerged in water of density 1000 kg/m3,and (b) when it is entirely out of the water?

A 200-kg flat-bottomed boat floats in fresh water,which has a density of 1000 kg/m3.If the base of the boat is 1.42 m wide and 4.53 m long,to what depth is the bottom of the boat submerged when it carries three passengers whose total mass is 257kg?

A rectangular wooden block measures 10.0 cm × 4.00 cm × 2.00 cm.When the block is placed in water,it floats horizontally,with its bottom face 1.65 cm below the surface.What is the density of the wood? The density of water is 1.00 g/cm3.

When a container of water is placed on a laboratory scale,the scale reads 120 g.Now a 20-g piece of copper (of density 8.9 g/cm3) is suspended from a thread and lowered into the water,not touching the bottom of the container.What will the scale now read? The density of water is 1.0 g/cm3.

Water,which we can treat as ideal and incompressible,flows at 12 m/s in a horizontal pipe with a pressure of 3.0 × 104 Pa.If the pipe widens to twice its original radius,what is the pressure in the wider section?

As a rock sinks deeper and deeper into water of constant density,what happens to the buoyant force on it if it started above the surface of the water?

A circular window 30 cm in diameter in a submarine can withstand a net maximum force of 5.20 × 105 N without damage.What is the maximum depth in a fresh-water lake to which the submarine can go without damaging the window? The density of fresh water is 1000 kg/m3.

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?

A round coin has a diameter of 19.55 mm,a thickness of 1.55 mm,and a mass of 2.50 g.What is its density?

A 4.7-kg solid sphere,made of metal whose density is 4,000 kg/ m³. hangs by a light cord.When the sphere is immersed in water,what is the tension in the cord? The density of water is 1000 kg/m³.

The density of material at the center of a neutron star is approximately 1.00 × 10¹⁸ kg/m³.What is the mass of a cube of this material that is On each side.(One micron is equal to 1.00 × 10^-6 m. )

What force does the water exert (in addition to that due to atmospheric pressure) on a submarine window of radius 44.0 cm at a depth of 9,400 m in sea water? The density of sea water is 1025 kg/m³.

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 crane lifts a steel submarine of density 7800 kg/m³ and mass 20,000 kg.What is the tension in the lifting cable (a) when the submarine is submerged in water of density 1000 kg/m³,and (b) when it is entirely out of the water?

A 200-kg flat-bottomed boat floats in fresh water,which has a density of 1000 kg/m³.If the base of the boat is 1.42 m wide and 4.53 m long,to what depth is the bottom of the boat submerged when it carries three passengers whose total mass is 257kg?

A rectangular wooden block measures 10.0 cm × 4.00 cm × 2.00 cm.When the block is placed in water,it floats horizontally,with its bottom face 1.65 cm below the surface.What is the density of the wood? The density of water is 1.00 g/cm³.

When a container of water is placed on a laboratory scale,the scale reads 120 g.Now a 20-g piece of copper (of density 8.9 g/cm³) is suspended from a thread and lowered into the water,not touching the bottom of the container.What will the scale now read? The density of water is 1.0 g/cm³.

Water,which we can treat as ideal and incompressible,flows at 12 m/s in a horizontal pipe with a pressure of 3.0 × 10⁴ Pa.If the pipe widens to twice its original radius,what is the pressure in the wider section?

A circular window 30 cm in diameter in a submarine can withstand a net maximum force of 5.20 × 10⁵ N without damage.What is the maximum depth in a fresh-water lake to which the submarine can go without damaging the window? The density of fresh water is 1000 kg/m³.