Chapter 11-15

Does the air exert a buoyant force on all objects in air or only on objects such as balloons that are very light for their size?

Air exerts a buoyant force on all objects.

Which of the following has the greatest outer surface area?

An elephant

Rank from most to least, the amount of lift on the following airplane wings: A. Area 1000 m2 with atmospheric pressure difference of 2.0 N/m2. B. Area 800 m2 with atmospheric pressure difference of 2.4 N/m2. C. Area 600 m2 with atmospheric pressure difference of 3.8 N/m2. Rank from most to least. To rank items as equivalent, overlap them.

Area 600 m2 with atmospheric pressure difference of 3.8 N/m2. Area 1000 m2 with atmospheric pressure difference of 2.0 N/m2. Area 800 m2 with atmospheric pressure difference of 2.4 N/m2.

How does the arrangement of atoms in a crystalline substance differ from the arrangement in a noncrystalline (amorphous) substance?

Atoms in crystals are in an ordered array. In amorphous materials, they are randomly distributed.

What is a compound? Cite two examples.

Atoms of different elements with bonds between them: NaCl and H2O

What is a mixture? Cite two examples.

Atoms pressed together without bonding: air and salt and sand

Is it tension or compression that strengthens an arch that supports a load?

Compression

What happens to the volume of a loaf of bread that is squeezed? The mass? The density?

Decreases, stays the same, increases

What type of force holds atoms together in a crystal?

Electric

Which investigator is credited for discovering Brownian motion?

Robert Brown

What is the energy source for the motion of gas in the atmosphere? What prevents atmospheric gases from flying off into space?

Solar energy, gravity

What geometrical shape has the smallest surface area for a given volume?

Sphere

The periodic table of the elements is a list of __________.

atoms

Consider the set of tubes shown in the figure. Each tube contains an unknown fluid that is less dense than the water it floats on top of. Rank the four unknown fluids from least dense to most dense.

(A,C),B,D

Which one of these represents the largest amount of energy?

1 Calorie

If an object suspended by a scale shows a weight of 3 N in air, and 2 N when submerged in water, the buoyant force on the submerged object is __________.

1 N

Suppose that we repeat the experiment shown in the video, but we replace one of the cylinders with a cylinder that has twice the radius (and use larger containers of water). If the height of the original cylinder is h, how deeply must we submerge the new cylinder to get the same weight reduction as in the video?

1/4h To get the same reduction in weight, the same volume of cylinder must be submerged. The volume of a cylinder is V= πr2h, so if we double the radius, we must reduce the depth of immersion by a factor of four.

A 1 kg balloon at equilibrium in the air is buoyed up with a force of __________.

10 newtons

How much air must a 100-ton blimp displace to float and neither rise nor sink?

100 tons

Which one of these cites the lowest temperature?

270 K

How many shells are represented in the presently known periodic table?

7

Distinguish between a calorie and a Calorie

A Calorie is 1000 calories.

How does a molecule differ from an atom? Give an example.

A molecule is composed of two or more atoms bonded together: H2O.

How does a plasma differ from a gas?

A plasma is made up of ionized atoms.

Distinguish between tension and compression.

A pulled-apart object is in tension; a pushed-together one is in compression.

Consider these three animals: A. dog B. horse C. elephant Pt A. Rank them, from highest to lowest, for their surface areas. Pt B. Rank them, from highest to lowest, for their masses. Pt C. Rank them, from highest to lowest, for their weights. Pt D. Rank them, from highest to lowest, for their volumes. Pt E. Rank them, from highest to lowest, for their surface area per weight.

A-D. Elephant, Horse, Dog E. Dog, Horse, Elephant

In lab you find that a 1-kg rock suspended above water weighs 10 N . When the rock is suspended beneath the surface of the water, the scale reads 8.0 N . 10n 8n none? - 10n read ?read none? A.What is the buoyant force on the rock? B. If the container of water weighs 10 N on the weighing scale, what is the scale reading when the rock is suspended beneath the surface of the water? C. What is the scale reading when the rock is released and rests at the bottom of the container?

A. F = 2.0 N B. W = 12 N C. W = 20 N

A. When Dr. Hewitt immerses the object in water, how does the loss of weight of the object compare with the buoyant force of the water? B. When Dr. Hewitt immerses an object in water the second time and catches the water that is displaced by the object, how does the weight lost by the object compare to the weight of the water displaced? C. What is the buoyant force that acts on a submerged object equal to?

A. Loss of weight is equal to the buoyant force. B. The weight loss of the object is equal to the weight of the water displaced. C. The buoyant force is equal to the weight of the fluid displaced by the submerged object.

Rank, from smallest to largest, the pressures in the tank of motionless fluid shown in the figure. A. Highest B. Second highest, C and D equal on rim of conatiner E. Second lowest F. Lowest of em all

A. Smallest-----Largest A, (B,C,D) E, F "Equal"

A. What happens when Dr. Hewitt places a card on a glass full of colored water and turns it upside down? B. Why do the card and water do what they do when Dr. Hewitt flips them over? C. What happens when Dr. Hewitt takes the cans containing a small amount of hot water and dips them in cold water? D. Why do the cans containing a small amount of hot water do what they do in the experiment when Dr. Hewitt immerses them?

A. The card stays, and the water also stays in the glass. B. The card is held up by atmospheric pressure that balances the weight of water. C. The cans get crushed. D. When the cans are suddenly cooled, the pressure inside them is less than the atmospheric pressure outside.

A. Suppose you increase the height of the object WITHOUT changing its depth under water. What will happen to the force due to pressure on the bottom of the object? B. Suppose you increase the height of the object WITHOUT changing its depth under water. What will happen to the net buoyant force? C. Suppose you increase the depth of the object WITHOUT changing its height. What will happen to the force due to pressure on the bottom of the object? D. Suppose you increase the depth of the object WITHOUT changing its height. What will happen to the net buoyant force? E. On what factors does the buoyant force acting on an object depend?

A. The force due to pressure on the bottom of the object will increase. B. The net buoyant force will increase. C. The force due to pressure on the bottom of the object will increase. D. The net buoyant force will stay the same. E. height of the object

In 2009, one of the U.S. government's bailout packages was $700 billion when gold was worth $800 per ounce ($28.20 per gram). A. Calculate the mass in grams of $700 billion worth of gold. B. If this amount of gold were in the shape of a cube, how long would each of its sides be?

A. m = 2.48×1010 g B. L= 10.9m

A. What did Robert Brown see under the microscope? B. Why did the particles jiggle around? C. If you place a Styrofoam cup on the table and a bunch of BBs move around it randomly, what will happen to the cup, and why?

A. specks of dust moving around B. The particles were struck by atoms, but unequally on different sides. C. The cup will move randomly in different directions because the BBs will exert unequal forces on the cup in different directions.

Distinguish between adhesive and cohesive forces.

Adhesive forces are between unlike substances, whereas cohesive forces are between like substances.

As the text cites, atoms are incredibly tiny, numerous, perpetually moving, and what else?

Ageless

Estimate the buoyant force that air exerts on you. (To do this, you can estimate your volume by knowing your weight and by assuming that your weight density is a bit less than that of water.) Assume that your weight is a about 1000 N , for example.

F = 1.3 N

Why isn't there a horizontal buoyant force on a submerged object?

Force vectors on the sides cancel one another.

Which of the following has the greatest density?

Gold

What is the evidence that dark matter exists?

Gravitational forces within galaxies are too great to be accounted for with ordinary matter.

Rank the volume of air in the glass, from greatest to least, when it is held A. near the surface as shown. B. 1 m beneath the surface. C. 2 m beneath the surface

Greatest: near the surface as shown, 1 m beneath the surface, Least: 2 m beneath the surface

Which of the following is an element?

Hydrogen

Where in the atom is most of its mass concentrated? What is this mass composed of?

In the nucleus as protons and neutrons

A strong wind blows over the house shown in the figure. The wind is much stronger over the house's roof than lower down, and the house has an open chimney. A window on the ground floor is open, and so are the doors inside the house. Which way will air flow through the house?

In the window and out the chimney

By how much does the density of air increase when it is compressed to half its volume?

It doubles.

Distinguish between mass number and atomic mass.

Mass number is the number of nucleons; atomic mass is the total mass of an atom.

How does pressure relate to force?

Pressure is force per unit area.

Consider the following atoms: A. Selenium B. Sulfur. C. Carbon. D. Silicon. Most---Least PtA: Consult the periodic table and rank these atoms, from most to least, by their mass. Pt. B: Consult the periodic table and rank these atoms, from most to least, by their number of electrons. Pt C: Consult the periodic table and rank these atoms, from most to least, by their number of protons.

Pt A Selenium, Sulfur, Silcon, Carbon Pt B Selenium, Sulfur, Silicon, Carbon Pt C Selenium, Sulfur, Silicon, Carbon

Rank the number of shells in these noble-gas atoms from most to least: A. Argon. B. Radon. C. Helium. D. Neon

Radon, Argon, Neon, Helium

Which of these is most elastic?

Steel

What is Hooke's law? Does it apply to elastic materials or to inelastic materials?

Stretch is proportional to force for elastic materials.

Each of the following items states a temperature, but does not tell you whether the temperature is measured on the Fahrenheit, Celsius, or Kelvin scale. Match the items to the appropriate temperature scale.

Temp F A hot summer day might be 100 Ice cream is stored in freezers at 26. Temp C Liquid water boils at 100. Water freezes into ice at 0. A typical room temperature is 24. Temp K The coldest possible temperature is 0. Water boils into gas phase at 373.15.

Consider the video tutorial you just watched. Suppose we repeat the experiment, but this time place the divider closer to one side of the tube than to the other. How will the speed of the air on the wide and narrow sides of the divider compare? (Assume that burning has a negligible effect on the mass of the air circulating through the tube.)

The air will move faster on the narrow side.

How is the energy value of foods determined?

The food is burned and the energy released is measured.

What happens to the internal pressure in a fluid flowing in a horizontal pipe when its speed increases?

The pressure decreases when the speed increases.

What happens to the pressure in all parts of a confined fluid if the pressure in one part is increased?

The pressure everywhere increases by the same amount.

How does pressure at the bottom of a body of water relate to the weight of water above each square meter of the bottom surface?

The pressure is the weight of the water divided by 1 m2.

What change in pressure occurs in a party balloon that is squeezed to one-third its volume with no change in temperature?

The pressure will increase to three times its original pressure.

Is there a distinction between thermal energy and internal energy? Which term do physicists prefer?

Thermal energy emphasizes heat flow, whereas internal energy is the grand total of all energies inside a substance. Physicists prefer internal energy.

What occurs when a proton and an antiproton meet?

They annihilate each other.

How does the weight of mercury in a barometer compare with the weight of an equal cross-section of air from sea level to the top of the atmosphere?

They are equal.

Which is denser: an object that has a density of 1000 kg/m3 or one that has a density of 1 g/cm3?

They are the same density.

A merchant in Katmandu sells you a solid gold 1.00-kg statue for a very reasonable price. When you get home, you wonder whether or not you got a bargain, so you lower the statue into a container of water and measure the volume of displaced water. A. Find the volume of water that will be displaced for pure gold.

V = 51.8 cm3

Does the buoyant force on a submerged object depend on the volume of the object or on the weight of the object?

Volume

On a perfect fall day, you are hovering at low altitude in a hot-air balloon, accelerated neither upward nor downward. The total weight of the balloon, including its load and the hot air in it, is 25000 N . A. Find the weight of the displaced air. B. Find the volume of the displaced air.

W = 2.5×104 N V = 2100 m3

Why do we say that a blob of putty is inelastic?

When deformed, it does not return to its original shape.

Why do we say that a spring is elastic?

When deformed, it returns to its original shape.

How do matter and antimatter differ?

When matter and antimatter meet, they annihilate in a flash of energy.

Air pressure over the surface of a bird's wings decreases when __________.

air speed increases there

Atmospheric pressure decreases with increasing _________.

altitude

Water pressure in a lake is greater __________.

at the bottom

The atomic masses of two isotopes of cobalt are 59 and 60. What is the number of protons in each?

cobalt-59, cobalt-60 = 27,27 protons

The pressure increases on a block resting on a table when you increase the __________.

downward force on the block

The buoyant force on a floating object is __________.

equal to the object's weight

To become a negative ion, does an atom lose or gain an electron?

gains

The weight of the atmosphere above 1 m2 of Earth's surface is about 100,000 N. Density, of course, becomes less with altitude. But suppose the density of air were a constant 1.2 kg/m3. Calculate where the top of the atmosphere would be.

h = 8.5 km

An important feature of atoms is that they __________.

have wave properties

Capillarity is a liability for __________.

insects in water

To become a positive ion, does an atom lose or gain an electron?

loses

Surface tension is caused by __________.

molecular attractions

The charge in the nucleus of an antimatter hydrogen atoms is __________.

negative

An object having the same density as water will __________.

neither sink nor float in water

When a tree branch is bent, the region in the center of the branch is the __________.

neutral layer

Suppose that we replace the aluminum with a mystery metal and repeat the experiment in the video. As in the video, the mass of the metal is the same as that of the water. Room temperature is about 20∘C before the start of the experiment. The water heats up to 40∘C, and the mystery metal heats up to 80∘C. Compared to that of water, the heat capacity of our mystery metal is View Available Hi

one-third as great. Given the same input of energy, the temperature of the metal increased three times as much as the temperature of the water. Therefore, the metal has one-third the heat capacity of water. (Recall that the heat Q delivered to a substance can be written Q = mc ΔT, where m is the mass of the substance and c is its heat capacity.)

Dark matter is considered to be __________.

plentiful in the universe

When a party balloon is compressed to one-third its volume, gas pressure in the balloon ___________.

triples

A stone submerged in water displaces the _________.

volume of water

Atmospheric pressure is mainly due to the ___________.

weight of air

A certain spring stretches 6.0 cm when a load of 34 N is suspended from it. How much will the spring stretch if 48 N is suspended from it (and it doesn't reach its elastic limit)?

x = 8.5 cm