Exam 2 Flashcards
Ch. 5-11
Density
mass / volume
(m divided by v)
Pressure
Force / area
(f divided by a)
How would you describe water pressure?
the greater the depth, the greater the pressure.
depth dependent and not volume dependent.
How does a water tower work?
the force of gravity acting on the water in a tall tower produces pressure in pipes below that supply many homes with reliable water pressure.
What is Archimedes’ Principle?
Bouyant force is equal to the weight of the displaced fluid. It can also be understood by pressure differences.
True or false: Archimedes’ Principle only applies to liquids.
False, AP applies to liquids and gasses (fluids).
True or False: More dense substances sink to the bottom while less dense substances float to the top.
True
Define gas pressure
Gas pressure is a measure of the amount of force per area that a gas exerts against containing walls.
Explain atmospheric pressure
caused by the weight of the air.
varries from one locality to another.
not uniform.
measurements are used to predict weather conditions.
what is a barometer?
a device used to measure atmospheric pressure
what is an aneroid barometer?
a small portable instrument that measures atmospheric pressure
What is a manual water pump?
Pumps air out of the pipes.
air pressure pushes the water up into the pipe.
what is a mechanical water pump?
Mechanical water pumps depend on electricity instead of atmospheric pressure (no 33.8m limit).
What is the density of air?
1.293 g/L
What does Bernoulli’s principle (continuous flow) tell us?
Where the speed of fluid increases, internal pressure in the fluid decreases. This applies to a smooth, steady flow.
How does a straw work?
as you suck on the straw, the air pressure draws the liquid up the straw.
Would an astronaut be able to use a straw in space?
no, because there is no air pressure to draw the liquid up.
What are the measurements of atmospheric pressure?
14.7 psi (pounds per square inch)
760 mm Hg (millimeters of mercury)
30 in Hg (inches of mercury)
1 atm (atmosphere)
What is Absolute Zero?
The lowest limit of temperature.
As temperature of a gas changes, ___________ of a gas changes.
Volume
What is the definition of heat?
Energy being transferred from one object to another.
What is the natural direction of heat flow?
From a warmer substance to a cooler substance.
What is Thermodynamics?
The movement of temperature.
Explain the first law of thermodynamics.
When heat is added to a system:
it can raise the temperature
it can be used to do work
Energy can neither be created nor destroyed.