Question 1

A wooden log floats in a river (density 1000 kg/m3), with one-quarter above the water, carried toward the sea (density 1025 kg/m3) by the river current. What will be the change in the percentage of the volume of log above water when it comes to the sea?

Accepted Answer

A) The log will go up 2%. 
B) The log will go down 2%. 
C) The log will go up 27%. 
D) The log will go down 27%.

Question 2

Gauge pressure is the ratio of pressure to ambient (air) pressure.

Accepted Answer

A) True 
 B)False

Question 3

What is the apparent weight of an object immersed in a vessel filled with water, in a weightless environment, such as the International Space station?

Accepted Answer

The answer of What is the apparent weight of an...

Question 4

A metal cube fully submerged in water shows an apparent weight of 1.9 N. When completely submerged in acetone, its apparent weight is 2.2 N. What is the length of the side of the cube? (Note: The density of water is ñwater = 1000 kg/m3 and of acetone ñacetone = 784 kg/m3.)

Accepted Answer

A) 5.0 × 10-2 m 
B) 2.5 × 10-3 m 
C) 1.4 × 10-4 m 
D) We need to know the mass of the cube to calculate the length.

Question 5

The density of ice is 917 kg/m³, and the density of sea water is 1025 kg/m³. A walrus climbs onto a piece of floating ice that has a volume of 15.7 m³. How much does the walrus weigh if the ice is just submerged under the surface of water?

Accepted Answer

The answer of The density of ice is 917 kg/m³,...

Question 6

A rock is sinking in the water. Which one of these statements correctly describes the buoyant force?

Accepted Answer

A) It is zero. 
B) It is equal to the weight of the wood. 
C) It is equal to all the other forces acting on the wood, but opposite in direction. 
D) It is equal in magnitude but opposite in direction of the weight of the wood.

Question 7

If no changes occur in a fluid, we say that it is in equilibrium. This statement includes all parameters of both macroscopic and microscopic motion of fluid molecules.

Accepted Answer

A) True 
 B)False

Question 8

Buoyant force is sometimes directed upward and sometimes downward, depending on whether the object is sinking or floating.

Accepted Answer

A) True 
 B)False

Question 9

Nautilus, a mollusk inside a spiral shell, sometimes dives as deep as 400 m below the ocean surface during the day in order to avoid heating by the sun. By what factor is the pressure exerted on the shell at that depth larger than the pressure at 60 m depth, where nautilus usually feeds on plankton? (Note: The density of sea water is ñ = 1030 kg/m³.)

Accepted Answer

The answer of Nautilus, a mollusk inside a spiral shell,...

Question 10

Figure 11.2: A hydraulic lift 
-Hydraulic lift is shown in Fig. 11.2. The diameter of a large piston is 0.4 m. What is the diameter of a small piston if we can use a force of 147 N to lift a car of a mass 1500 kg?

Accepted Answer

The answer of Figure 11.2: A hydraulic lift 
-Hydraulic lift...

Question 11

A body sinking in a fluid with terminal velocity has a weight equal to the buoyant force and the force of friction.

Accepted Answer

A) True 
 B)False

Question 12

What is the transmural ratio between a soap bubble of diameter D and another one with double the diameter, 2D?

Accepted Answer

A) The pressure in a bubble with diameter D is 2 times larger than in the 2D bubble. 
B) The pressure in a bubble with diameter D is 2 times smaller than in the 2D bubble. 
C) The pressure in a bubble with diameter D is 2ð times larger than in the 2D bubble. 
D) The pressure in a bubble with diameter D is 2ð times smaller than in the 2D bubble.

Question 13

A 0.25 kg balloon is filled with helium. If the balloon is a sphere with a radius of 4 m, what is the maximum number of standard men it can lift? (Note: The density of air is ñair = 1.20 kg/m3 and of helium ñhelium = 0.179 kg/m3; standard man has a mass of 70 kg.)

Accepted Answer

A) 3 standard men 
B) 4 standard men 
C) 6 standard men 
D) 38 standard men

Question 14

A body is immersed in a fluid. Which of these statements correctly describes buoyant force?

Accepted Answer

A) It is equal to the weight of the object. 
B) It is equal to the weight of the fluid displaced by the object. 
C) It is equal to the pressure of water below the object. 
D) It is equal to the mass of the fluid displaced by the object.

Question 15

What unit is used to measure surface tension?

Accepted Answer

A) N m 
B) Pa 
C) kg/s2 
D) kg m/s2

Question 16

A piece of wood is floating on the water. Which one of these statements correctly describes buoyant force?

Accepted Answer

A) It is zero. 
B) It is equal to the weight of the wood. 
C) It is equal to all the other forces acting on the wood, but is opposite in direction. 
D) It is equal in magnitude but opposite in direction to the weight of the wood.

Question 17

An air bubble is 50 cm below the surface of a lake. In that case, we assume that the bubble has only one surface to generate surface tension. The gauge pressure inside the bubble is 6.0 × 103 Pa. What is radius of the bubble? (The density of the water is ñH2O = 1000 kg/m3, and the surface tension is ó = 0.073 N/m.)

Accepted Answer

A) 2.6 × 10-4 m 
B) 1.3 × 10-4 m 
C) 6.0 × 10-7 m 
D) 3.0 × 10-7 m

Question 18

What would the perimeter of each foot have to be to enable a standard man (70 kg) to stand on the water on both feet, held up by surface tension? (Note: Surface tension for water ó = 0.073 N/m.)

Accepted Answer

A) 9.3 × 103 m 
B) 4.7 × 103 m 
C) 9.6 × 102 m 
D) 4.8 × 102 m

Question 19

If the radius of a capillary tube decreases by 3 times, the water will rise to triple its original height.

Accepted Answer

A) True 
 B)False

Question 20

We can breathe in and out as long as the pressure between the outside and the inside of the lungs is lower than 0.05 times normal atmospheric pressure. How deep can we snorkel in sea water with density ñ = 1.025 × 10³ kg/m³, and in fresh water with density ñ = 1.0 × 10³ kg/m³?

Accepted Answer

The answer of We can breathe in and out as...

Exam 11: Static Fluids

A wooden log floats in a river (density 1000 kg/m³) , with one-quarter above the water, carried toward the sea (density 1025 kg/m³) by the river current. What will be the change in the percentage of the volume of log above water when it comes to the sea?

Gauge pressure is the ratio of pressure to ambient (air) pressure.

What is the apparent weight of an object immersed in a vessel filled with water, in a weightless environment, such as the International Space station?

A metal cube fully submerged in water shows an apparent weight of 1.9 N. When completely submerged in acetone, its apparent weight is 2.2 N. What is the length of the side of the cube? (Note: The density of water is ñ_water = 1000 kg/m³ and of acetone ñ_acetone = 784 kg/m³.)

The density of ice is 917 kg/m³, and the density of sea water is 1025 kg/m³. A walrus climbs onto a piece of floating ice that has a volume of 15.7 m³. How much does the walrus weigh if the ice is just submerged under the surface of water?

A rock is sinking in the water. Which one of these statements correctly describes the buoyant force?

If no changes occur in a fluid, we say that it is in equilibrium. This statement includes all parameters of both macroscopic and microscopic motion of fluid molecules.

Buoyant force is sometimes directed upward and sometimes downward, depending on whether the object is sinking or floating.

Figure 11.2: A hydraulic lift -Hydraulic lift is shown in Fig. 11.2. The diameter of a large piston is 0.4 m. What is the diameter of a small piston if we can use a force of 147 N to lift a car of a mass 1500 kg?

A body sinking in a fluid with terminal velocity has a weight equal to the buoyant force and the force of friction.

What is the transmural ratio between a soap bubble of diameter D and another one with double the diameter, 2D?

A 0.25 kg balloon is filled with helium. If the balloon is a sphere with a radius of 4 m, what is the maximum number of standard men it can lift? (Note: The density of air is ñ_air = 1.20 kg/m³ and of helium ñ_helium = 0.179 kg/m³; standard man has a mass of 70 kg.)

A body is immersed in a fluid. Which of these statements correctly describes buoyant force?

What unit is used to measure surface tension?

A piece of wood is floating on the water. Which one of these statements correctly describes buoyant force?

What would the perimeter of each foot have to be to enable a standard man (70 kg) to stand on the water on both feet, held up by surface tension? (Note: Surface tension for water ó = 0.073 N/m.)

If the radius of a capillary tube decreases by 3 times, the water will rise to triple its original height.

We can breathe in and out as long as the pressure between the outside and the inside of the lungs is lower than 0.05 times normal atmospheric pressure. How deep can we snorkel in sea water with density ñ = 1.025 × 10³ kg/m³, and in fresh water with density ñ = 1.0 × 10³ kg/m³?

Exam 11: Static Fluids

A wooden log floats in a river (density 1000 kg/m3) , with one-quarter above the water, carried toward the sea (density 1025 kg/m3) by the river current. What will be the change in the percentage of the volume of log above water when it comes to the sea?

Gauge pressure is the ratio of pressure to ambient (air) pressure.

What is the apparent weight of an object immersed in a vessel filled with water, in a weightless environment, such as the International Space station?

A metal cube fully submerged in water shows an apparent weight of 1.9 N. When completely submerged in acetone, its apparent weight is 2.2 N. What is the length of the side of the cube? (Note: The density of water is ñwater = 1000 kg/m3 and of acetone ñacetone = 784 kg/m3.)

The density of ice is 917 kg/m3, and the density of sea water is 1025 kg/m3. A walrus climbs onto a piece of floating ice that has a volume of 15.7 m3. How much does the walrus weigh if the ice is just submerged under the surface of water?

A rock is sinking in the water. Which one of these statements correctly describes the buoyant force?

If no changes occur in a fluid, we say that it is in equilibrium. This statement includes all parameters of both macroscopic and microscopic motion of fluid molecules.

Buoyant force is sometimes directed upward and sometimes downward, depending on whether the object is sinking or floating.

Figure 11.2: A hydraulic lift -Hydraulic lift is shown in Fig. 11.2. The diameter of a large piston is 0.4 m. What is the diameter of a small piston if we can use a force of 147 N to lift a car of a mass 1500 kg?

A body sinking in a fluid with terminal velocity has a weight equal to the buoyant force and the force of friction.

What is the transmural ratio between a soap bubble of diameter D and another one with double the diameter, 2D?

A 0.25 kg balloon is filled with helium. If the balloon is a sphere with a radius of 4 m, what is the maximum number of standard men it can lift? (Note: The density of air is ñair = 1.20 kg/m3 and of helium ñhelium = 0.179 kg/m3; standard man has a mass of 70 kg.)

A body is immersed in a fluid. Which of these statements correctly describes buoyant force?

What unit is used to measure surface tension?

A piece of wood is floating on the water. Which one of these statements correctly describes buoyant force?

What would the perimeter of each foot have to be to enable a standard man (70 kg) to stand on the water on both feet, held up by surface tension? (Note: Surface tension for water ó = 0.073 N/m.)

If the radius of a capillary tube decreases by 3 times, the water will rise to triple its original height.

We can breathe in and out as long as the pressure between the outside and the inside of the lungs is lower than 0.05 times normal atmospheric pressure. How deep can we snorkel in sea water with density ñ = 1.025 × 103 kg/m3, and in fresh water with density ñ = 1.0 × 103 kg/m3?

A wooden log floats in a river (density 1000 kg/m³) , with one-quarter above the water, carried toward the sea (density 1025 kg/m³) by the river current. What will be the change in the percentage of the volume of log above water when it comes to the sea?

A metal cube fully submerged in water shows an apparent weight of 1.9 N. When completely submerged in acetone, its apparent weight is 2.2 N. What is the length of the side of the cube? (Note: The density of water is ñ_water = 1000 kg/m³ and of acetone ñ_acetone = 784 kg/m³.)

The density of ice is 917 kg/m³, and the density of sea water is 1025 kg/m³. A walrus climbs onto a piece of floating ice that has a volume of 15.7 m³. How much does the walrus weigh if the ice is just submerged under the surface of water?

A 0.25 kg balloon is filled with helium. If the balloon is a sphere with a radius of 4 m, what is the maximum number of standard men it can lift? (Note: The density of air is ñ_air = 1.20 kg/m³ and of helium ñ_helium = 0.179 kg/m³; standard man has a mass of 70 kg.)

We can breathe in and out as long as the pressure between the outside and the inside of the lungs is lower than 0.05 times normal atmospheric pressure. How deep can we snorkel in sea water with density ñ = 1.025 × 10³ kg/m³, and in fresh water with density ñ = 1.0 × 10³ kg/m³?