Question 1

A 50-cm3 block of wood is floating on water,and a 50-cm3 chunk of iron is totally submerged in the water.On which one the water exerts the greater buoyant force?

Accepted Answer

A) on the wood 
B) on the iron 
C) The same buoyant force is exerted on both. 
D) It cannot be determined without knowing their densities. 
A) on the wood 
B) on the iron 
C) The same buoyant force is exerted on both. 
D) It cannot be determined without knowing their densities. B

Question 2

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

A) The absolute (total)pressure does not change. 
B) The absolute (total)pressure increases, but by an amount less than Δp. 
C) The absolute (total)pressure increases by Δp. 
D) The gauge pressure increases by Δp. 
E) The gauge pressure does not change. 
A) The absolute (total)pressure does not change. 
B) The absolute (total)pressure increases, but by an amount less than Δp. 
C) The absolute (total)pressure increases by Δp. 
D) The gauge pressure increases by Δp. 
E) The gauge pressure does not change. C,E

Question 3

A cubical block of stone is lowered at a steady rate into the ocean by a crane,always keeping the top and bottom faces horizontal.Which one of the following graphs best describes the buoyant force B exerted on this block by the water as a function of time t if the block just enters the water at time t = 0 s?

Accepted Answer

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

Question 4

A hot air balloon along with its cargo has a mass of 4.0 x 105 kg,and it holds 7.0 x 105 m3 of hot air.It is floating at a constant height in air with a density of 1.29 kg/m3.What is the density of the hot air in the balloon?

Accepted Answer

A) 1.4 kg/m3 
B) 0.72 kg/m3 
C) 0.57 kg/m3 
D) 0.86 kg/m3 
E) 0.43 kg/m3 
A) 1.4 kg/m3 
B) 0.72 kg/m3 
C) 0.57 kg/m3 
D) 0.86 kg/m3 
E) 0.43 kg/m3

Question 5

A container has a vertical tube,whose inner radius is 24.00 mm,connected to it at its side,as shown in the figure.An unknown liquid reaches level A in the container and level B in the tube-level A being 5.0 cm higher than level B.The liquid supports a 20-cm high column of oil,between levels B and C,whose density is $570 \mathrm {~kg} / \mathrm { m } ^ { 3 }$ The mass of the oil is closest to

Accepted Answer

A) 210 
B) 410 
C) 620 
D) 820 
E) 1000 
A) 210 
B) 410 
C) 620 
D) 820 
E) 1000

Question 6

A cubical box 25.0 cm on each side is immersed in a fluid.The pressure at the top surface of the box is 109.40 kPa and the pressure on the bottom surface is 112.00 kPa.What is the density of the fluid?

Accepted Answer

A) 1000 kg/m3 
B) 1030 kg/m3 
C) 1060 kg/m3 
D) 1090 kg/m3 
E) 1120 kg/m3 
A) 1000 kg/m3 
B) 1030 kg/m3 
C) 1060 kg/m3 
D) 1090 kg/m3 
E) 1120 kg/m3

Question 7

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

A) the liquid-water level remains flush with the rim of the glass. 
B) the liquid water level rises, causing water to run down the outside of the glass. 
C) the liquid-water level decreases. 
A) the liquid-water level remains flush with the rim of the glass. 
B) the liquid water level rises, causing water to run down the outside of the glass. 
C) the liquid-water level decreases.

Question 8

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 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 initial force that oil must exert on the smaller piston in order to start lifting the car? For purposes of this problem,neglect the mass of the pistons.

Accepted Answer

A) 727 N 
B) 926 N 
C) 2.90 kN 
D) 3.33 kN 
E) 1.20 kN 
A) 727 N 
B) 926 N 
C) 2.90 kN 
D) 3.33 kN 
E) 1.20 kN

Question 9

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

A) more. 
B) less. 
C) the same. 
D) Cannot be determined because we do not know the volume of the ship. 
A) more. 
B) less. 
C) the same. 
D) Cannot be determined because we do not know the volume of the ship.

Question 10

A solid sphere of mass 8.6 kg,made of metal whose density is 3400 kg/ $m ^ { 3 }$ ,hangs by a cord.When the sphere is immersed in a liquid of unknown density,the tension force that the cord exerts on the sphere is 38 N.The density of the liquid is closest to which one of the following values?

Accepted Answer

A) 1900 kg/ $m ^ { 3 }$ 
B) 1700 kg/ $m ^ { 3 }$ 
C) 1600 kg/ $m ^ { 3 }$ 
D) 1500 kg/ $m ^ { 3 }$ 
E) 1400 kg/ $m ^ { 3 }$ 
A) 1900 kg/ $m ^ { 3 }$ 
B) 1700 kg/ $m ^ { 3 }$ 
C) 1600 kg/ $m ^ { 3 }$ 
D) 1500 kg/ $m ^ { 3 }$ 
E) 1400 kg/ $m ^ { 3 }$

Question 11

A container has a vertical tube,whose inner radius is 12.00 mm,connected to it at its side,as shown in the figure.An unknown liquid reaches level A in the container and level B in the tube-level A being 5.0 cm higher than level B.The liquid supports a 20-cm high column of oil,between levels B and C,whose density is $320 \mathrm {~kg} / \mathrm { m } ^ { 3 }$ The gauge pressure at level B is closest to

Accepted Answer

A) 630 Pa 
B) 310 Pa 
C) 470 Pa 
D) 790 Pa 
E) 940 Pa 
A) 630 Pa 
B) 310 Pa 
C) 470 Pa 
D) 790 Pa 
E) 940 Pa

Question 12

A cylinder,semicircular in cross-section,is 10 m long and 5.0 m in radius.It is completely submerged,with its flat bottom side horizontal and 8.0 m below the water surface,as shown in the figure.What is the magnitude of the net force on the curved upper surface of the half-cylinder? Neglect atmospheric pressure.

Accepted Answer

A) 2.0 × 106 N 
B) 2.5 × 106 N 
C) 3.0 × 106 N 
D) 3.5 × 106 N 
E) 4.0 × 106 N 
A) 2.0 × 106 N 
B) 2.5 × 106 N 
C) 3.0 × 106 N 
D) 3.5 × 106 N 
E) 4.0 × 106 N

Question 13

As a rock sinks deeper and deeper into water of constant density,what happens to the buoyant force exerted on it by water 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. 
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 14

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 9400 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 
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 15

A 200-N object floats with three-fourths of its volume beneath the surface of the water.What is the buoyant force exerted by the water on the object? The density of water is 1000 kg/m3.

Accepted Answer

A) 50 N 
B) 150 N 
C) 200 N 
D) 267 N 
E) It cannot be determined because we do not know the volume of the object. 
A) 50 N 
B) 150 N 
C) 200 N 
D) 267 N 
E) It cannot be determined because we do not know the volume of the object.

Question 16

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

Question 17

A cylindrical rod of length 12 cm and diameter 2.0 cm will just barely float in water of density 1000 kg/m3.What is its mass?

Accepted Answer

A) 38 g 
B) 75 g 
C) 150 g 
D) 300 g 
A) 38 g 
B) 75 g 
C) 150 g 
D) 300 g

Question 18

A 550- N person empties her lungs as much as possible and is then completely immersed in water of density 1000 kg/m3 while suspended from a harness connected to a spring scale.The spring scale reads now 21.2 N.What is her density?

Accepted Answer

A) 1050 kg/m3 
B) 1040 kg/m3 
C) 1030 kg/m3 
D) 960 kg/m3 
E) 56.1 kg/m3 
A) 1050 kg/m3 
B) 1040 kg/m3 
C) 1030 kg/m3 
D) 960 kg/m3 
E) 56.1 kg/m3

Question 19

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

Accepted Answer

A) A 
B) B 
C) C 
D) D 
E) The pressure is the same at each of the labeled points. 
A) A 
B) B 
C) C 
D) D 
E) The pressure is the same at each of the labeled points.

Question 20

A 4.7-kg solid sphere,made of metal whose density is 4000 kg/ $m ^ { 3 }$ ,hangs by a light cord.When the sphere is immersed in water,what is the tension force the cord exerts on the sphere? 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 
A) 35 N 
B) 40 N 
C) 46 N 
D) 52 N 
E) 58 N

Exam 11: Static Fluids

A 50-cm3 block of wood is floating on water,and a 50-cm3 chunk of iron is totally submerged in the water.On which one the water exerts the greater buoyant force?

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.)

A hot air balloon along with its cargo has a mass of 4.0 x 105 kg,and it holds 7.0 x 105 m3 of hot air.It is floating at a constant height in air with a density of 1.29 kg/m3.What is the density of the hot air in the balloon?

A cubical box 25.0 cm on each side is immersed in a fluid.The pressure at the top surface of the box is 109.40 kPa and the pressure on the bottom surface is 112.00 kPa.What is the density of the fluid?

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,

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

A solid sphere of mass 8.6 kg,made of metal whose density is 3400 kg/ m3m ^ { 3 }m3 ,hangs by a cord.When the sphere is immersed in a liquid of unknown density,the tension force that the cord exerts on the sphere is 38 N.The density of the liquid is closest to which one of the following values?

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

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 9400 m in sea water? The density of sea water is 1025 kg/m3.

A 200-N object floats with three-fourths of its volume beneath the surface of the water.What is the buoyant force exerted by the water on the object? 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

A cylindrical rod of length 12 cm and diameter 2.0 cm will just barely float in water of density 1000 kg/m3.What is its mass?

A 550- N person empties her lungs as much as possible and is then completely immersed in water of density 1000 kg/m3 while suspended from a harness connected to a spring scale.The spring scale reads now 21.2 N.What is her density?

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

A 4.7-kg solid sphere,made of metal whose density is 4000 kg/ m3m ^ { 3 }m3 ,hangs by a light cord.When the sphere is immersed in water,what is the tension force the cord exerts on the sphere? The density of water is 1000 kg/m3.

Introduction

Kinematics: Motion in One Dimension

Newtonian Mechanics

Applying Newtons Laws

Circular Motion

Impulse and Linear Momentum

Work and Energy

Extended Bodies at Rest

Rotational Motion

Gases

Fluids in Motion

First Law of Thermodynamics

Second Law of Thermodynamics

Electric Charge force and Energy

The Electric Field

Dc Circuits

Magnetism

Electromagnetic Induction

Vibrational Motion

Mechanical Waves

Reflection and Refraction

Mirrors and Lenses

Wave Optics

Electromagnetic Waves

Special Relativity

Quantum Optics

Atomic Physics

Nuclear Physics

Particle Physics

Filters

A 50-cm³ block of wood is floating on water,and a 50-cm³ chunk of iron is totally submerged in the water.On which one the water exerts the greater buoyant force?

A hot air balloon along with its cargo has a mass of 4.0 x 10⁵ kg,and it holds 7.0 x 10⁵ m³ of hot air.It is floating at a constant height in air with a density of 1.29 kg/m³.What is the density of the hot air in the balloon?

A solid sphere of mass 8.6 kg,made of metal whose density is 3400 kg/ $m ^ { 3 }$ ,hangs by a cord.When the sphere is immersed in a liquid of unknown density,the tension force that the cord exerts on the sphere is 38 N.The density of the liquid is closest to which one of the following values?

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 9400 m in sea water? The density of sea water is 1025 kg/m³.

A 200-N object floats with three-fourths of its volume beneath the surface of the water.What is the buoyant force exerted by the water on the object? The density of water is 1000 kg/m³.

A cylindrical rod of length 12 cm and diameter 2.0 cm will just barely float in water of density 1000 kg/m³.What is its mass?

A 550- N person empties her lungs as much as possible and is then completely immersed in water of density 1000 kg/m³ while suspended from a harness connected to a spring scale.The spring scale reads now 21.2 N.What is her density?

A 4.7-kg solid sphere,made of metal whose density is 4000 kg/ $m ^ { 3 }$ ,hangs by a light cord.When the sphere is immersed in water,what is the tension force the cord exerts on the sphere? The density of water is 1000 kg/m³.