Physics Chapter 20 Flashcards

Questions and Answers

What is the atmosphere?

Earth's atmosphere consists of molecules that occupy space and extends many kilometers above Earth's surface.

What causes atmospheric pressure?

Atmospheric pressure is caused by the weight of air.

What is a barometer?

An instrument used for measuring the pressure of the atmosphere.

How does a simple mercury barometer show pressure?

The height of the mercury in the tube is a measure of the atmospheric pressure. Signup and view all the answers

What is an aneroid barometer?

An instrument that measures variations in atmospheric pressure without a liquid. Signup and view all the answers

How does an aneroid barometer work?

It uses a small metal box that is partially exhausted of air, with a flexible lid that bends with pressure changes. Signup and view all the answers

What does Boyle's law state?

The product of pressure and volume for a given mass of gas is a constant as long as the temperature does not change. Signup and view all the answers

What causes an object to rise?

Any object less dense than the air around it will rise. Signup and view all the answers

What does Bernoulli's principle state?

When the speed of a fluid increases, pressure in the fluid decreases. Signup and view all the answers

What are streamlines?

The smooth path of a small region of fluid in a steady flow. Signup and view all the answers

What is an eddy?

Changing, curling paths in turbulent flow of a fluid. Signup and view all the answers

What is lift?

The upward force created by the difference between the air pressure above and below the wing. Signup and view all the answers

How is horizontal flight possible?

When lift equals weight, horizontal flight is possible. Signup and view all the answers

Study Notes

Earth's Atmosphere

The atmosphere is composed of various molecules that extend many kilometers above the Earth's surface.
It plays a crucial role in supporting life and influencing weather patterns.

Atmospheric Pressure

Caused by the weight of air, similar to how water pressure results from the weight of water.
Measured using various instruments to understand its effects on weather and flight.

Barometer Types

Barometer: An instrument designed to measure atmospheric pressure.
Mercury Barometer: Uses mercury in a tube; the height of the mercury indicates atmospheric pressure.
Aneroid Barometer: Measures pressure changes using a flexible metal box that responds to variations in air pressure.

Boyle's Law

States the product of pressure and volume remains constant for a given mass of gas when temperature is held steady.
Key principle used in understanding gas behavior under varying pressure conditions.

Buoyancy

An object will rise if it is less dense than the surrounding air, demonstrating principles of buoyancy.

Bernoulli's Principle

Highlights that an increase in fluid speed results in a decrease in fluid pressure, essential in understanding how lift is generated.

Fluid Dynamics

Streamlines: Represent the smooth path of fluid motion in a steady flow, crucial for visualizing fluid behavior.
Eddies: Defined as turbulent, changing paths in fluid flow, showcasing complex fluid dynamics.

Lift and Flight

Lift is the upward force resulting from the pressure difference between the air above and below a wing.
Horizontal flight is achievable when lift balances with the weight of the aircraft, enabling stable flight.

Description

Explore the key concepts of Earth's atmosphere with these flashcards. This quiz covers definitions and explanations related to atmospheric pressure, barometers, and the composition of air. Perfect for students looking to reinforce their understanding of physics concepts in Chapter 20.