Question 1

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 2

A person weighing 900 N is standing on snowshoes.Each snowshoe has area 2500 cm2 and has negligible weight.What pressure does this person's weight exert on the snow?

Accepted Answer

A) 0.18 N/m2 
B) 0.36 N/m2 
C) 1800 N/m2 
D) 3600 N/m2 
A) 0.18 N/m2 
B) 0.36 N/m2 
C) 1800 N/m2 
D) 3600 N/m2

Question 3

In a section of horizontal pipe with a diameter of 3.0 cm,the pressure is 100 kPa and water is flowing with a speed of 1.5 m/s.The pipe narrows to 2.0 cm.What is the pressure in the narrower region? Treat the water as an ideal incompressible fluid.

Accepted Answer

A) 95 kPa 
B) 48 kPa 
C) 44 kPa 
D) 230 kPa 
E) 67 kPa 
A) 95 kPa 
B) 48 kPa 
C) 44 kPa 
D) 230 kPa 
E) 67 kPa

Question 4

An ideal incompressible fluid flows at 12 m/s in a horizontal pipe.If the pipe widens to twice its original radius,what is the flow speed in the wider section?

Accepted Answer

A) 12 m/s 
B) 6.0 m/s 
C) 4.0 m/s 
D) 3.0 m/s 
A) 12 m/s 
B) 6.0 m/s 
C) 4.0 m/s 
D) 3.0 m/s

Question 5

In a hydraulic garage lift,the small piston has a radius of 5.0 cm and the large piston has a radius of 15 cm.What force must be applied on the small piston in order to lift a car weighing 20,000 N on the large piston? Assume the pistons each have negligible weight.

Accepted Answer

A) 6.7 × 103 N 
B) 5.0 × 103 N 
C) 2.9 × 103 N 
D) 2.2 × 103 N 
A) 6.7 × 103 N 
B) 5.0 × 103 N 
C) 2.9 × 103 N 
D) 2.2 × 103 N

Question 6

When you blow some air above a paper strip,the paper rises.This happens because

Accepted Answer

A) the air above the paper moves faster and the pressure is higher. 
B) the air above the paper moves faster and the pressure is lower. 
C) the air above the paper moves faster and the pressure remains constant. 
D) the air above the paper moves slower and the pressure is higher. 
E) the air above the paper moves slower and the pressure is lower. 
A) the air above the paper moves faster and the pressure is higher. 
B) the air above the paper moves faster and the pressure is lower. 
C) the air above the paper moves faster and the pressure remains constant. 
D) the air above the paper moves slower and the pressure is higher. 
E) the air above the paper moves slower and the pressure is lower.

Question 7

A hollow steel ball of diameter 3.0 m just barely floats in water.What is the wall thickness of the ball? (ρFe = 7.87 g/cm3,ρwater = 1.00 g/cm3)

Accepted Answer

A) 6.6 cm 
B) 37 cm 
C) 131 cm 
D) 79 cm 
A) 6.6 cm 
B) 37 cm 
C) 131 cm 
D) 79 cm

Question 8

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

A) in salt water 
B) in fresh water 
C) The buoyant force is the same in both cases. 
A) in salt water 
B) in fresh water 
C) The buoyant force is the same in both cases.

Question 9

A pressurized cylindrical tank,5.0 m in diameter,contains water that emerges from the pipe at point C with a speed of  
As shown in the figure.Point A is 10 m above point B and point C is 3.0 m above point B.The area of the pipe at point B is  
And the pipe narrows to an area of  
At point C.Assume that the water is an ideal fluid in laminar flow.The density of water is 1000 kg/m3 The mass flow rate in the pipe is closest to

Accepted Answer

A) 520 Kg/s. 
B) 470 Kg/s. 
C) 420 Kg/s. 
D) 360 Kg/s. 
E) 310 Kg/s. 
A) 520 Kg/s. 
B) 470 Kg/s. 
C) 420 Kg/s. 
D) 360 Kg/s. 
E) 310 Kg/s.

Question 10

Consider a very small hole in the bottom of a tank that is  
In diameter and filled with water to a height of  
Find the speed at which the water exits the tank through the hole.

Accepted Answer

A) 4.20 m/s 
B) 17.64 m/s 
C) 44.1 m/s 
D) 48.3 m/s 
A) 4.20 m/s 
B) 17.64 m/s 
C) 44.1 m/s 
D) 48.3 m/s

Question 11

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.

Question 12

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

A) The pressure everywhere in the oil will increase by Δp. 
B) The pressure at the bottom of the oil will increase by more than Δp. 
C) The pressure at the top of the oil will increase by less than Δp. 
D) The pressure on the sides of the chamber will not increase. 
E) The increase in the force on the top of the chamber will be the same as the increase in the force on the bottom of the chamber. 
A) The pressure everywhere in the oil will increase by Δp. 
B) The pressure at the bottom of the oil will increase by more than Δp. 
C) The pressure at the top of the oil will increase by less than Δp. 
D) The pressure on the sides of the chamber will not increase. 
E) The increase in the force on the top of the chamber will be the same as the increase in the force on the bottom of the chamber.

Question 13

A polar bear of mass 200 kg stands on an ice floe that is a uniform 1.0 m thick.What is the minimum area of the floe that will just support the bear in saltwater of density 1030 kg/m3? The density of ice is 980 kg/m3.

Accepted Answer

A) 1.0 m2 
B) 2.0 m2 
C) 3.0 m2 
D) 4.0 m2 
A) 1.0 m2 
B) 2.0 m2 
C) 3.0 m2 
D) 4.0 m2

Question 14

A person who weighs 550 N empties her lungs as much as possible and is then completely immersed in water of density 1000 kg/m3 while suspended from a harness.Her apparent weight is 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 15

Water flows out of a large reservoir through 5.0-cm diameter pipe.The pipe connects to a 3.0-cm diameter pipe that is open to the atmosphere,as shown in the figure.What is the speed of the water in the 5.0-cm pipe? Treat the water as an ideal incompressible fluid.

Accepted Answer

A) 2.3 m/s 
B) 3.2 m/s 
C) 3.9 m/s 
D) 8.9 m/s 
E) 10 m/s 
A) 2.3 m/s 
B) 3.2 m/s 
C) 3.9 m/s 
D) 8.9 m/s 
E) 10 m/s

Question 16

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

A) 2 ρ 
B) 4 ρ 
C) ρ   
D) ρ   
E) 8 ρ 
A) 2 ρ 
B) 4 ρ 
C) ρ   
D) ρ   
E) 8 ρ

Question 17

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

A) the aluminum 
B) the lead 
C) Both have the same buoyant force. 
D) It cannot be determined without knowing their volumes. 
A) the aluminum 
B) the lead 
C) Both have the same buoyant force. 
D) It cannot be determined without knowing their volumes.

Question 18

Glycerin,with a viscosity of 1.5 N ∙ s/m2,is flowing with an average speed of 1.2 m/s through a tube that has a radius of 5.0 mm and is 25 cm long.What is the drop in pressure over the length of this pipe?

Accepted Answer

A) 140 kPa 
B) 46 kPa 
C) 72 kPa 
D) 76 kPa 
E) 130 kPa 
A) 140 kPa 
B) 46 kPa 
C) 72 kPa 
D) 76 kPa 
E) 130 kPa

Question 19

A fluid is flowing with an average speed of 1.5 m/s through a tube that has a radius of 2.0 mm and is 18 cm long.The drop in pressure is 967 Pa.What is the viscosity of the fluid?

Accepted Answer

A) 0.0018 N ∙ s/m2 
B) 0.0056 N ∙ s/m2 
C) 0.028 N ∙ s/m2 
D) 0.013 N ∙ s/m2 
E) 0.0034 N ∙ s/m2 
A) 0.0018 N ∙ s/m2 
B) 0.0056 N ∙ s/m2 
C) 0.028 N ∙ s/m2 
D) 0.013 N ∙ s/m2 
E) 0.0034 N ∙ s/m2

Question 20

A 4.0-kg cylinder of solid iron is supported by a string while submerged in water.What is the tension in the string? The density of iron is 7860 kg/m3 and that of water is 1000 kg/m3.

Accepted Answer

A) 2.5 N 
B) 20 N 
C) 24 N 
D) 34 N 
E) 40 N 
A) 2.5 N 
B) 20 N 
C) 24 N 
D) 34 N 
E) 40 N

Exam 15: Fluids

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 person weighing 900 N is standing on snowshoes.Each snowshoe has area 2500 cm2 and has negligible weight.What pressure does this person's weight exert on the snow?

In a section of horizontal pipe with a diameter of 3.0 cm,the pressure is 100 kPa and water is flowing with a speed of 1.5 m/s.The pipe narrows to 2.0 cm.What is the pressure in the narrower region? Treat the water as an ideal incompressible fluid.

An ideal incompressible fluid flows at 12 m/s in a horizontal pipe.If the pipe widens to twice its original radius,what is the flow speed in the wider section?

In a hydraulic garage lift,the small piston has a radius of 5.0 cm and the large piston has a radius of 15 cm.What force must be applied on the small piston in order to lift a car weighing 20,000 N on the large piston? Assume the pistons each have negligible weight.

When you blow some air above a paper strip,the paper rises.This happens because

A hollow steel ball of diameter 3.0 m just barely floats in water.What is the wall thickness of the ball? (ρFe = 7.87 g/cm3,ρwater = 1.00 g/cm3)

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 very small hole in the bottom of a tank that is In diameter and filled with water to a height of Find the speed at which the water exits the tank through the hole.

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 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 polar bear of mass 200 kg stands on an ice floe that is a uniform 1.0 m thick.What is the minimum area of the floe that will just support the bear in saltwater of density 1030 kg/m3? The density of ice is 980 kg/m3.

A person who weighs 550 N empties her lungs as much as possible and is then completely immersed in water of density 1000 kg/m3 while suspended from a harness.Her apparent weight is now 21.2 N.What is her density?

Water flows out of a large reservoir through 5.0-cm diameter pipe.The pipe connects to a 3.0-cm diameter pipe that is open to the atmosphere,as shown in the figure.What is the speed of the water in the 5.0-cm pipe? Treat the water as an ideal incompressible fluid.

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 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?

Glycerin,with a viscosity of 1.5 N ∙ s/m2,is flowing with an average speed of 1.2 m/s through a tube that has a radius of 5.0 mm and is 25 cm long.What is the drop in pressure over the length of this pipe?

A fluid is flowing with an average speed of 1.5 m/s through a tube that has a radius of 2.0 mm and is 18 cm long.The drop in pressure is 967 Pa.What is the viscosity of the fluid?

A 4.0-kg cylinder of solid iron is supported by a string while submerged in water.What is the tension in the string? The density of iron is 7860 kg/m3 and that of water is 1000 kg/m3.

Introduction to Physics

One-Dimensional Kinematics

Vectors in Physics

Two-Dimensional Kinematics

Newtons Laws of Motion

Applications of Newtons Laws

Work and Kinetic Energy

Potential Energy and Conservation of Energy

Linear Momentum and Collisions

Rotational Kinematics and Energy

Rotational Dynamics and Static Equilibrium

Gravity

Oscillations About Equilibrium

Waves and Sound

Temperature and Heat

Phases and Phase Changes

The Laws of Thermodynamics

Electric Charges, Forces, and Fields

Electric Potential and Electric

Electric Current and Direct-Current Circuits

Magnetism

Magnetic Flux and Faradays Law of Induction

Alternating-Current Circuits

Electromagnetic Waves

Geometrical Optics

Optical Instruments

Physical Optics: Interference and Diffraction

Relativity

Quantum Physics

Atomic Physics

Nuclear Physics and Nuclear Radiation

Filters

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 person weighing 900 N is standing on snowshoes.Each snowshoe has area 2500 cm² and has negligible weight.What pressure does this person's weight exert on the snow?

A hollow steel ball of diameter 3.0 m just barely floats in water.What is the wall thickness of the ball? (ρ_Fe = 7.87 g/cm³,ρ_water= 1.00 g/cm³)

A polar bear of mass 200 kg stands on an ice floe that is a uniform 1.0 m thick.What is the minimum area of the floe that will just support the bear in saltwater of density 1030 kg/m³? The density of ice is 980 kg/m³.

A person who weighs 550 N empties her lungs as much as possible and is then completely immersed in water of density 1000 kg/m³ while suspended from a harness.Her apparent weight is now 21.2 N.What is her density?

Glycerin,with a viscosity of 1.5 N ∙ s/m²,is flowing with an average speed of 1.2 m/s through a tube that has a radius of 5.0 mm and is 25 cm long.What is the drop in pressure over the length of this pipe?

A 4.0-kg cylinder of solid iron is supported by a string while submerged in water.What is the tension in the string? The density of iron is 7860 kg/m³ and that of water is 1000 kg/m³.