Question 1

A plastic block of dimensions 2.00 cm × 3.00 cm × 4.00 cm has a mass of 30.0 g.What is its density?

Accepted Answer

Density is defined as mass per unit volume. The mass of the block is given as 30.0 g. The volume of the block is calculated by multiplying its dimensions:

Volume = (2.00 cm) × (3.00 cm) × (4.00 cm) = 24.00 cm³

So the density of the block is:

Density = mass / volume = 30.0 g / 24.00 cm³ = 1.25 g/cm³

Therefore, the answer is C, 1.25 g/cm³.

Question 2

Calculate the pressure exerted on the ground due to the weight of 
Person standing on one foot.if the bottom of the person's foot is 
Wide and 
Long.

Accepted Answer

The answer of Calculate the pressure exerted on the ground...

Question 3

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

Accepted Answer

The buoyant force on an object is equal to the weight of the fluid displaced by the object. Since the iron is completely submerged, it displaces more water than the floating wood, assuming both have the same volume. Therefore, the iron experiences a greater buoyant force.

Question 4

A piece of wood is floating in a bathtub.A second piece of wood sits on top of the first piece,and does not touch the water.If the top piece is taken off and placed in the water,what happens to the water level in the tub?

Accepted Answer

The water level in the tub is determined by the total volume of the pieces of wood and any other objects in the tub. Since the second piece of wood was already sitting on top of the first piece and not touching the water, its volume was already accounted for in the original water level. When it is placed in the water, it displaces an equal volume of water, so the water level stays the same.

Question 5

Under standard conditions,the density of air is 1.29 kg/m³.What is the mass of the air inside a room measuring 4.0 m × 3.0 m × 2.0 m?

Accepted Answer

The volume of the room is:

V = 4.0 m x 3.0 m x 2.0 m = 24.0 m^3

The mass of air inside the room is:

m = ρV = 1.29 kg/m^3 x 24.0 m^3 = 31 kg

Therefore, the best choice is C.

Question 6

A brick weighs 50.0 N,and measures 30.0 cm × 10.0 cm × 4.00 cm.What is the maximum pressure it can exert on a horizontal surface due to its weight?

Accepted Answer

The maximum pressure the brick can exert on a surface is when it is placed on its smallest surface area, which is 10.0 cm x 4.0 cm = 40.0 cm^2.

To calculate the pressure exerted by the weight of the brick, we divide the weight by the area:

Pressure = weight / area
Pressure = 50.0 N / 0.0040 m^2
Pressure = 12,500 Pa = 12.5 kPa

Therefore, the correct answer is D) 12.5 kPa.

Question 7

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

The answer of Water flows through a pipe.The diameter of...

Question 8

A 1938 nickel has a diameter of 21.21 mm,a thickness of 1.95 mm,and weighs 0.04905 N.What is its density?

Accepted Answer

The answer of A 1938 nickel has a diameter of...

Question 9

A compressed gas with a total mass of 
Is stored in a spherical container having a radius of 0.521 m.What is the density of the compressed gas?

Accepted Answer

The answer of A compressed gas with a total mass...

Question 10

One of the dangers of tornados and hurricanes is the rapid drop in air pressure that is associated with such storms.Assume that the air pressure inside of a sealed house is 1.02 atm when a hurricane hits.The hurricane rapidly decreases the external air pressure to 0.910 atm.What net outward force is exerted on a square window of the house that is On each side? (1.00 atm = 1.01 × 10⁵ Pa)

Accepted Answer

The answer of One of the dangers of tornados and...

Question 11

How many grams of ethanol (density 0.80 g/cm³)should be added to 5.0 g of chloroform (density 1.5 g/cm³)if the resulting mixture is to have a density of 1.2 g/cm³? Assume that the fluids do not change their volumes when they are mixed.

Accepted Answer

The correct answer is A.The density of the mixture is given by:$$ho = \frac{m_{ethanol} + m_{chloroform}}{V_{ethanol} + V_{chloroform}}$$where $ho$ is the density of the mixture, $m_{ethanol}$ is the mass of ethanol, $m_{chloroform}$ is the mass of chloroform, $V_{ethanol}$ is the volume of ethanol, and $V_{chloroform}$ is the volume of chloroform.We can assume that the volumes of the fluids do not change when they are mixed, so:$$V_{ethanol} + V_{chloroform} = V_{mixture}$$where $V_{mixture}$ is the volume of the mixture.We can also write:$$V_{ethanol} = \frac{m_{ethanol}}{ho_{ethanol}}$$and$$V_{chloroform} = \frac{m_{chloroform}}{ho_{chloroform}}$$where $ho_{ethanol}$ is the density of ethanol and $ho_{chloroform}$ is the density of chloroform.Substituting these expressions into the equation for the density of the mixture, we get:$$ho = \frac{m_{ethanol} + m_{chloroform}}{\frac{m_{ethanol}}{ho_{ethanol}} + \frac{m_{chloroform}}{ho_{chloroform}}}$$Solving for $m_{ethanol}$, we get:$$m_{ethanol} = \frac{ho_{mixture} - ho_{chloroform}}{ho_{ethanol} - ho_{mixture}} 	imes m_{chloroform}$$Substituting the given values, we get:$$m_{ethanol} = \frac{1.2 g/cm^3 - 1.5 g/cm^3}{0.80 g/cm^3 - 1.2 g/cm^3} 	imes 5.0 g = 2.0 g$$Therefore, the correct answer is A.

Question 12

Two horizontal pipes have the same diameter,but pipe B is twice as long as pipe A.Water undergoes viscous flow in both pipes,subject to the same pressure difference across the lengths of the pipes.If the flow rate in pipe B is Q = 
What is the flow rate in pipe A?

Accepted Answer

The answer of Two horizontal pipes have the same diameter,but...

Question 13

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

Accepted Answer

When air is blown above the paper strip, it accelerates and moves faster than the stagnant air below the paper. According to Bernoulli's principle, as the speed of a fluid (in this case, air) increases, the pressure it exerts decreases. Therefore, the pressure above the paper decreases, causing the higher-pressure air below the paper to push the paper upward. This is why the paper rises.

Question 14

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

The answer of The density of material at the center...

Question 15

Two horizontal pipes are the same length,but pipe B has twice the diameter of pipe A.Water undergoes viscous flow in both pipes,subject to the same pressure difference across the lengths of the pipes.If the flow rate in pipe A is Q = 
,what is the flow rate in pipe B?

Accepted Answer

The answer of Two horizontal pipes are the same length,but...

Question 16

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

The answer of A person weighing 900 N is standing...

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

The buoyant force on an object increases as it displaces more fluid, up until it is fully submerged. Once fully submerged, the buoyant force remains constant, as it is equal to the weight of the fluid displaced by the object, according to Archimedes' principle.

Question 18

A 100-kg person sits on a 5-kg bicycle.The total weight is borne equally by the two wheels of the bicycle.The tires are 2.0 cm wide and are inflated to a gauge pressure of 8.0 × 10⁵ Pa.What length of each tire is in contact with the ground?

Accepted Answer

The total weight of the person and the bicycle is $100\, \text{kg} + 5\, \text{kg} = 105\, \text{kg}$. The force due to gravity acting on this total mass is $F = mg = 105\, \text{kg} \times 9.8\, \text{m/s}^2 = 1029\, \text{N}$. Since the weight is equally distributed between the two wheels, each wheel bears half the total force, so $F_{\text{per wheel}} = \frac{1029\, \text{N}}{2} = 514.5\, \text{N}$.The pressure $P$ is given by the force $F$ divided by the area $A$ in contact with the ground, $P = \frac{F}{A}$. The gauge pressure inside the tires is given as $8.0 \times 10^5\, \text{Pa}$, and this is the pressure exerted outward by the air inside the tire against the ground (and thus the pressure with which the tire pushes against the ground).Rearranging the pressure equation to solve for the area $A = \frac{F}{P}$, and knowing that the length of the tire in contact with the ground $L$ is related to the area by $A = L \times \text{width of the tire}$, we can solve for $L$.Given that the width of the tire is $2.0\, \text{cm} = 0.02\, \text{m}$, we have:$$L = \frac{F_{\text{per wheel}}}{P \times \text{width}} = \frac{514.5\, \text{N}}{8.0 \times 10^5\, \text{Pa} \times 0.02\, \text{m}} = \frac{514.5}{16000} = 0.032125\, \text{m} = 3.2\, \text{cm}$$Therefore, the length of each tire in contact with the ground is 3.2 cm.

Question 19

The weight of a 1200-kg car is supported equally by the four tires,which are inflated to the same gauge pressure.What gauge pressure is required so the area of contact of each tire with the road is 100 cm²?

Accepted Answer

The total weight of the car is supported equally by the four tires, so the weight supported by each tire is:

W = 1200 kg / 4 = 300 kg

The area of contact of each tire with the road is given as 100 cm^2.

We can use the formula:

P = F / A

Where P is the gauge pressure, F is the force on the tire, and A is the area of contact.

Substituting the given values, we get:

P = (300 kg × 9.8 m/s^2) / (100 cm^2 × 10^-4 m^2)

P = 2.94 × 10^5 Pa

Converting to gauge pressure (subtracting atmospheric pressure of 1 atm), we get:

P = 2.94 × 10^5 - 1 atm = 2.9 × 10^5 Pa = 2.9 × 10^1 kPa

Rounding to two significant figures, the answer is:

Choice C) 2.9 × 10^1 kPa (or 2.9 × 10^4 Pa)

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

To find the density, use the formula: Density = Mass/Volume. First, convert the dimensions to meters: diameter = 0.01955 m, thickness = 0.00155 m. Calculate the volume of the coin using the formula for the volume of a cylinder: V = πr²h = π(0.01955/2)²(0.00155). Then, convert the mass to kg: 2.50 g = 0.0025 kg. Finally, calculate the density: Density = 0.0025 kg / Volume. The result is approximately 5.37 × 10³ kg/m³.

Quiz 15: Fluids

A plastic block of dimensions 2.00 cm × 3.00 cm × 4.00 cm has a mass of 30.0 g.What is its density?

Calculate the pressure exerted on the ground due to the weight of Person standing on one foot.if the bottom of the person's foot is Wide and Long.

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

A piece of wood is floating in a bathtub.A second piece of wood sits on top of the first piece,and does not touch the water.If the top piece is taken off and placed in the water,what happens to the water level in the tub?

Under standard conditions,the density of air is 1.29 kg/m³.What is the mass of the air inside a room measuring 4.0 m × 3.0 m × 2.0 m?

A brick weighs 50.0 N,and measures 30.0 cm × 10.0 cm × 4.00 cm.What is the maximum pressure it can exert on a horizontal surface due to its weight?

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?

A 1938 nickel has a diameter of 21.21 mm,a thickness of 1.95 mm,and weighs 0.04905 N.What is its density?

A compressed gas with a total mass of Is stored in a spherical container having a radius of 0.521 m.What is the density of the compressed gas?

How many grams of ethanol (density 0.80 g/cm³) should be added to 5.0 g of chloroform (density 1.5 g/cm³) if the resulting mixture is to have a density of 1.2 g/cm³? Assume that the fluids do not change their volumes when they are mixed.

Two horizontal pipes have the same diameter,but pipe B is twice as long as pipe A.Water undergoes viscous flow in both pipes,subject to the same pressure difference across the lengths of the pipes.If the flow rate in pipe B is Q = What is the flow rate in pipe A?

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

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. )

Two horizontal pipes are the same length,but pipe B has twice the diameter of pipe A.Water undergoes viscous flow in both pipes,subject to the same pressure difference across the lengths of the pipes.If the flow rate in pipe A is Q = ,what is the flow rate in pipe B?

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?

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 100-kg person sits on a 5-kg bicycle.The total weight is borne equally by the two wheels of the bicycle.The tires are 2.0 cm wide and are inflated to a gauge pressure of 8.0 × 10⁵ Pa.What length of each tire is in contact with the ground?

The weight of a 1200-kg car is supported equally by the four tires,which are inflated to the same gauge pressure.What gauge pressure is required so the area of contact of each tire with the road is 100 cm²?

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?

Quiz 15: Fluids

A plastic block of dimensions 2.00 cm × 3.00 cm × 4.00 cm has a mass of 30.0 g.What is its density?

Calculate the pressure exerted on the ground due to the weight of Person standing on one foot.if the bottom of the person's foot is Wide and Long.

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

A piece of wood is floating in a bathtub.A second piece of wood sits on top of the first piece,and does not touch the water.If the top piece is taken off and placed in the water,what happens to the water level in the tub?

Under standard conditions,the density of air is 1.29 kg/m3.What is the mass of the air inside a room measuring 4.0 m × 3.0 m × 2.0 m?

A brick weighs 50.0 N,and measures 30.0 cm × 10.0 cm × 4.00 cm.What is the maximum pressure it can exert on a horizontal surface due to its weight?

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?

A 1938 nickel has a diameter of 21.21 mm,a thickness of 1.95 mm,and weighs 0.04905 N.What is its density?

A compressed gas with a total mass of Is stored in a spherical container having a radius of 0.521 m.What is the density of the compressed gas?

How many grams of ethanol (density 0.80 g/cm3) should be added to 5.0 g of chloroform (density 1.5 g/cm3) if the resulting mixture is to have a density of 1.2 g/cm3? Assume that the fluids do not change their volumes when they are mixed.

Two horizontal pipes have the same diameter,but pipe B is twice as long as pipe A.Water undergoes viscous flow in both pipes,subject to the same pressure difference across the lengths of the pipes.If the flow rate in pipe B is Q = What is the flow rate in pipe A?

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

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. )

Two horizontal pipes are the same length,but pipe B has twice the diameter of pipe A.Water undergoes viscous flow in both pipes,subject to the same pressure difference across the lengths of the pipes.If the flow rate in pipe A is Q = ,what is the flow rate in pipe B?

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?

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 100-kg person sits on a 5-kg bicycle.The total weight is borne equally by the two wheels of the bicycle.The tires are 2.0 cm wide and are inflated to a gauge pressure of 8.0 × 105 Pa.What length of each tire is in contact with the ground?

The weight of a 1200-kg car is supported equally by the four tires,which are inflated to the same gauge pressure.What gauge pressure is required so the area of contact of each tire with the road is 100 cm2?

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 50-cm³ block of wood is floating on water,and a 50-cm³ chunk of iron is totally submerged in the water.Which one has the greater buoyant force on it?

Under standard conditions,the density of air is 1.29 kg/m³.What is the mass of the air inside a room measuring 4.0 m × 3.0 m × 2.0 m?

How many grams of ethanol (density 0.80 g/cm³) should be added to 5.0 g of chloroform (density 1.5 g/cm³) if the resulting mixture is to have a density of 1.2 g/cm³? Assume that the fluids do not change their volumes when they are mixed.

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. )

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 100-kg person sits on a 5-kg bicycle.The total weight is borne equally by the two wheels of the bicycle.The tires are 2.0 cm wide and are inflated to a gauge pressure of 8.0 × 10⁵ Pa.What length of each tire is in contact with the ground?

The weight of a 1200-kg car is supported equally by the four tires,which are inflated to the same gauge pressure.What gauge pressure is required so the area of contact of each tire with the road is 100 cm²?