Introduction to Fluids - Key Terms

What is a fluid?

• A substance that has a fixed shape

• A substance that flows easily, such as liquids or gases

• A device that controls fluid flow

• The resistance of a liquid to flow

Answer explanation

A fluid is defined as a substance that flows easily, which includes both liquids and gases. This distinguishes it from solids, which have a fixed shape, and other options that describe properties or devices related to fluids.

What is viscosity?

• The measure of mass in a given volume

• The ability of an object to float in a fluid

• The resistance of a liquid to flow

• The physical form of a substance

Answer explanation

Viscosity is defined as the resistance of a liquid to flow. It describes how thick or sticky a fluid is, affecting how easily it moves. The other options do not accurately represent this property.

What does hydraulics refer to?

• The ability of a substance to flow

• The use of liquid pressure to perform work

• The amount of fluid in a container

• The resistance of fluids to flow

Answer explanation

Hydraulics specifically refers to the use of liquid pressure to perform work, making it essential in various applications like machinery and vehicles. The other options do not accurately define hydraulics.

Match the following descriptions with their corresponding terms.

• Buoyancy

• The ability of an object to float in a fluid

• Density

• A device that controls the flow of fluid

• Viscosity

• The amount of mass in a given volume

• Valve

• The resistance of a liquid to flow

Answer explanation

Buoyancy refers to the ability of an object to float in a fluid. It is the upward force exerted by the fluid that counteracts the weight of the object, allowing it to remain on the surface or rise.

What is a valve?

• A device that controls the flow of a fluid

• The ability of a fluid to float

• A form of liquid pressure

• The measure of how dense a fluid is

Answer explanation

A valve is specifically defined as a device that controls the flow of a fluid, making the first answer choice correct. The other options describe different fluid properties but do not define a valve.

What does density refer to?

• The resistance of a liquid to flow

• The measure of how much mass is contained in a given volume

• The ability of an object to float

• A device that controls fluid flow

Answer explanation

Density is defined as the measure of how much mass is contained in a given volume. This means it quantifies the compactness of a substance, making the second answer choice the correct one.

Match the following descriptions with the correct states of matter.

• Have definite shape but no definite volume

• Solids and liquids only

• Exist in three primary forms

• Gases and liquids only

• Can flow and take the shape of their container

• Solid, liquid, gas

• Have definite shape and volume

• Solids and gases only

Answer explanation

The states of matter include solid, liquid, and gas. Each state has distinct properties: solids have a fixed shape, liquids take the shape of their container, and gases fill the available space. Thus, the correct answer is 'Solid, liquid, gas'.

Tags

NGSS.MS-PS1-4

What is buoyancy?

• The ability of a fluid to resist flow

• The upward force exerted by a fluid on an object

• The measure of fluid density

• The flow rate of a liquid

Answer explanation

Buoyancy is defined as the upward force exerted by a fluid on an object submerged in it. This force counteracts the weight of the object, allowing it to float or rise in the fluid.

What is Pascal's principle?

• The principle that states pressure applied to a confined fluid is transmitted undiminished throughout the fluid

• The principle that describes the buoyant force on an object submerged in a fluid

• The principle that explains the flow of electricity in a circuit

• The principle that defines the conservation of mass in a closed system

Answer explanation

Pascal's principle states that when pressure is applied to a confined fluid, it is transmitted equally in all directions. This explains why the correct choice is the first option, as it accurately describes this fundamental concept.

Bernoulli's equation is used for (a)  

• Calculating the density of a fluid
• Determining the pressure, velocity,
• Measuring the viscosity of a liquid
• Finding the buoyant force on an obj

Answer explanation

Bernoulli's equation relates the pressure, velocity, and height of a fluid in motion, making it essential for understanding fluid dynamics. The correct choice highlights this relationship, unlike the other options.