Physics Ch 14 textbook
plasma
4th phase of matter, exists at high temps in this phase matter consists of positively charged ions and free electrons
pressure and volume
? are inversely proportional
Vacuums
? are produced by pumps, which work by virtue of a gas tending to fill its container
Streamlines
? are the smooth paths of bits of fluid. The lines are closer together in narrower regions, where the flow speed is greater
density
? of air decreases with altitude
pressure
? of the atmosphere is not uniform. Besides altitude variations, atmospheric pressure varies from one locality to the next, and from day to day. This leads to moving weather fronts and storms that shape our weather. When a high-pressure system approaches, you can expect cooler temperatures and clear skies. When a low-pressure system approaches, expect warmer weather, rain, and storms
A gas-filled balloon will rise only so long as it displaces a weight of air greater than its own weight. Because air becomes less dense with altitude, a lesser weight of air is displaced per given volume as the balloon rises
A gas-filled balloon will rise only so long as it displaces a weight of air greater than its own weight. Because air becomes less dense with altitude, a lesser weight of air is displaced per given volume as the balloon rises
magnetohydrodynamic interaction
A higher-temperature plasma is the exhaust of a jet engine, a weakly ionized plasma. But when small amounts of potassium salts or cesium metal are added, it becomes a very good conductor and, when directed into a magnet, can generate electricity
pressure in the piston chamber is reduced to one-third. This is the principle that underlies a mechanical vacuum pump.
A piston in an airtight pump is withdrawn so that the volume of the air chamber is increased three times. What is the change in pressure?
lower
A vacuum pump simply provides a region of ? pressure into which fast-moving gas molecules randomly move. The air pressure is repeatedly lowered by piston and valve action
=
All bodies are buoyed up by a force ? to the weight of the air they displace
electrically charged
Although the electrons and ions are themselves ?, the plasma as a whole is electrically neutral because there are still equal numbers of positive and negative charges, just as there are in an ordinary gas
altimeter
An aneroid barometer calibrated for altitude is called an ? (altitude meter). Some ? are sensitive enough to indicate a change in elevation of less than a meter.
Archimedes' Principle
An object surrounded by air is buoyed up by a force equal to the weight of the air displaced.
rise /dense
Any object that has a mass that is less than the mass of an equal volume of air will? in air. Another way to say this is that any object less ? than air will rise in air
turbulent flow/eddies
At speeds above some critical point, however, the flow may become chaotic (called ?) and follow changing, curling paths called ?, This exerts friction on the fluid and dissipates some of its energy. Then Bernoulli's principle doesn't apply well.
conservation of energy
Bernoulli's principle is a consequence of the ?
pressure
By sucking on the straw placed in the drink, you reduce the air pressure in the straw. The weight of the atmosphere on the drink pushes liquid up into the reduced-pressure region inside the straw. Strictly speaking, the liquid is not sucked up; it is pushed up by the? of the atmosphere. If the atmosphere is prevented from pushing on the surface of the drink
balloon and jellyfish
Each is buoyed upward by a displaced weight of fluid equal to its own weight
speeds up / slows
For continuous flow, a fluid ? when it goes from a wide to a narrow part of the pipe and ? when it goes from a narrow to a wide part of the pipe
wider /narrower
For flow to be continuous in a confined region, it speeds up when moving from a ? region to a ? one.
If Earth's gravity were somehow turned off, atmospheric molecules would dissipate and disappear. Or if gravity acted but the molecules moved too slowly to form a gas (as might occur on a remote, cold planet), our "atmosphere" would be a liquid or solid layer, just so much more matter lying on the ground
If Earth's gravity were somehow turned off, atmospheric molecules would dissipate and disappear. Or if gravity acted but the molecules moved too slowly to form a gas (as might occur on a remote, cold planet), our "atmosphere" would be a liquid or solid layer, just so much more matter lying on the ground
higher
If a space with lower pressure is provided, gas will flow from the region of ? pressure to the region of lower pressure
If we say there is a force of suction, then we assume that a vacuum can exert a force. But what is a vacuum? It is an absence of matter; it is a condition of nothingness. How can nothing exert a force? The piston holding the weight up is not sucked upward. The piston is pushed upward by the weight of the atmosphere against its bottom surface.
If we say there is a force of suction, then we assume that a vacuum can exert a force. But what is a vacuum? It is an absence of matter; it is a condition of nothingness. How can nothing exert a force? The piston holding the weight up is not sucked upward. The piston is pushed upward by the weight of the atmosphere against its bottom surface.
Density is greatest at Earth's surface
In what part of the atmosphere is the greatest density of air
higher/lower.
Internal pressure is ? in slower-moving water in the wide part of the pipe, as evidenced by the more-squeezed air bubbles. The bubbles are bigger in the narrow part because the internal pressure there is ?
impulse
Internal pressure within flowing water and the external pressure it can exert when making impact on whatever it encounters are two different pressures. When the momentum of moving water (or anything else) is suddenly reduced, the ? it exerts can be huge.
There is a buoyant force acting on you, and you are buoyed upward by it. You don't notice it only because your weight is so much greater
Is there a buoyant force acting on you? If there is, why aren't you buoyed up by this force?
internal pressure,
It is important to distinguish between the pressure within a fluid, ? and the pressure exerted by the fluid on something that interferes with its flow
Plasmas on Earth are created in laboratories by heating gases to very high temperatures, making them so hot that electrons are "boiled" off the atoms. Plasmas may also be created at lower temperatures by bombarding atoms with high-energy particles or radiation.
Plasmas on Earth are created in laboratories by heating gases to very high temperatures, making them so hot that electrons are "boiled" off the atoms. Plasmas may also be created at lower temperatures by bombarding atoms with high-energy particles or radiation.
Since most balloons expand as they rise, their buoyancy stays fairly constant until they can't expand anymore. When the weight of the displaced air equals the total weight of the balloon, the upward motion of the balloon will cease
Since most balloons expand as they rise, their buoyancy stays fairly constant until they can't expand anymore. When the weight of the displaced air equals the total weight of the balloon, the upward motion of the balloon will cease
tires
Suppose that there are twice as many molecules in the same volume Then the air density is doubled. If the molecules move at the same average speed—or, equivalently, if they have the same temperature—then the number of collisions is doubled. This means that the pressure is doubled. So pressure is proportional to density.
The mercury is literally pushed up into the tube of a barometer by the weight of the atmosphere
The mercury is literally pushed up into the tube of a barometer by the weight of the atmosphere
pressure
The reason we don't feel this weight crushing against our bodies is that the ?inside our bodies balances the pressure of the surrounding air
water pressure
The volume of an air bubble depends on the surrounding ?. Where water gains speed, pressure is lowered and the bubbles become bigger. In water that slows, pressure is increased and the bubbles are squeezed to a smaller size.
They instead reduce the pressure in the straws and allow the weight of the atmosphere to push the liquid up into the straws.
They instead reduce the pressure in the straws and allow the weight of the atmosphere to push the liquid up into the straws.
density
We can also double the air ? by compressing the air to half its volume
compressing
We can also double the air density by ? the air to half its volume
half
We can also double the air density by compressing the air to ? its volume
When Torricelli tipped the mercury-filled tube upside down and placed it mouth downward in a dish of mercury, the mercury in the tube dropped to a level at which the weight of the mercury in the tube was balanced by the atmospheric force exerted on the reservoir. The empty space trapped above, except for some mercury vapor, is a vacuum. The vertical height of the mercury column remains constant even when the tube is tilted
When Torricelli tipped the mercury-filled tube upside down and placed it mouth downward in a dish of mercury, the mercury in the tube dropped to a level at which the weight of the mercury in the tube was balanced by the atmospheric force exerted on the reservoir. The empty space trapped above, except for some mercury vapor, is a vacuum. The vertical height of the mercury column remains constant even when the tube is tilted
water pump
When the handle is pumped, the air in the pipe is "thinned" as it expands to fill a larger volume. Atmospheric pressure on the well surface pushes water up into the pipe, causing water to overflow at the spout.
When the volume of a gas is decreased, its density and therefore pressure are increased.
When the volume of a gas is decreased, its density and therefore pressure are increased.
less
Where streamlines of a fluid are closer together, flow speed is greater and pressure within the fluid is ?
increases
Where the speed decreases, the internal pressure ? . This principle holds for smooth steady flow (called laminar flow) along streamlines of constant-density fluid
laminar flow
Where the speed decreases, the internal pressure increases. This principle holds for smooth steady flow (called ?) along streamlines of constant-density fluid
Bernoulli's Principle
Where the speed of a fluid increases, internal pressure in the fluid decreases
positive ion
a neutral atom has as many positive protons inside the nucleus as it has negative electrons outside the nucleus. When one or more of these electrons is stripped from the atom, the atom has more positive charge than negative charge and becomes a?
greater
air pressure that acts up against an object in air is ? than the air pressure above that pushes down
boyle law
applies to ideal gases. An ideal gas is one in which the disturbing effects of the forces between molecules and the finite size of the individual molecules can be ignored. Air and other gases under normal pressures approach ideal-gas conditions.
kinetic energy/gravity
atmosphere thickness is determined by two competing factors: the ? of its molecules, which tends to spread the molecules apart, and ?, which tends to hold them near Earth
If the atmospheric pressure increases, then the atmosphere pushes down harder on the mercury and the column of mercury is pushed higher than 76 cm
barometer "balances" when the weight of the liquid in the tube exerts the same pressure as the atmosphere outside
jellyfish and balloon
buoyancy, in both cases, is numerically equal to the weight of the fluid displaced
principle of continuity
change of speed with changing cross-section is a consequence
decrease of fluid pressure with increasing speed
decrease of fluid pressure with increasing speed
torricelli's barometer
device for measuring atmosphere pressure
evacuated,
greatest buoyancy would be achieved if a balloon were ?
plasma
is an electrified gas. The atoms that make it up are ionized, stripped of one or more electrons, with a corresponding number of free electrons
plasma dig from gas
it readily conducts electric current, absorbs certain kinds of radiation that pass unhindered through a gas, and can be shaped, molded, and moved by electric and magnetic fields
plasma
least common phase in our everyday environment, but it is the most prevalent phase of matter in the universe as a whole. The Sun and other stars are largely plasma
weight of the air
main cause of atmospheric pressure
aneroid barometer
measure atmospheric pressure
streamlines
motion of a fluid in steady flow follows imaginary
buoyed
objects in water are ? upward because the pressure that acts up against the bottom of the object exceeds the pressure that acts down against the top.
exceeds
objects in water are buoyed upward because the pressure that acts up against the bottom of the object ? the pressure that acts down against the top.
farm pump
operates by producing a partial vacuum in a pipe that extends down into the water below. The weight of the atmosphere on the surface of the water simply pushes the water up into the region of reduced pressure inside the pipe
inversely
pressure and volume are ? proportional
atmospheric pressure
pressure exerted against bodies immersed in the atmosphere resulting from the weight of air pressing down from above, at sea level this is 101kpa
Bernoulli's Principle
pressure in a fluid along a given streamline decreases as the speed of the fluid increases
Archimedes' Principle-for air and water
relationship between buoyancy and displaced fluid; an immersed object is buoyed up by a force equal to the weight of the fluid it displaces
boyle law
relationship between pressure and volume
higher/compression
the air pressure inside the inflated tires of an automobile is considerably ? than the atmospheric pressure outside. Due to ? , the density of the air inside is also greater than the density of the air outside
less dense
unlike water, the atmosphere becomes ? with altitude
elevation
uses a metal box that is partially exhausted of air and has a slightly flexible lid that bends in or out with changes in atmospheric pressure. The motion of the lid is indicated on a scale by a mechanical spring-and-lever system. Since the atmospheric pressure decreases with increasing altitude, a barometer can be used to determine ?
when the density of the balloon (including its load) equals the density of the surrounding air, the balloon will cease rising
when the density of the balloon (including its load) equals the density of the surrounding air, the balloon will cease rising
