physics exam 2

hw 5 and 6, review questions over fluid, temperature, and heat transfer, quiz 4 and 5

The mass of a cubic meter of water is

1000 kg

The buoyant force on an object is least when the object is

partly submerged

The concept of pressure involves both

force and area

When you stand with only one of your feet on a weighing scale, the scale reading is

the same as with both feet

A hospital patient confined to bed will be less likely to develop bed sores with a

water bed

One liter of water has a mass of

1 kg

A dam is thicker at the bottom than at the top mainly because

water pressure increases with depth

The buoyant force acting on a 10-ton ship floating in the ocean is

10 tons

A block of Styrofoam floats on water while a lead block of the same size block lies submerged in the water. The buoyant force is greatest on the

lead

When an object is partly or wholly immersed in a liquid, it is buoyed up

by a force equal to the weight of liquid displaced

What is the weight of water displaced by a 100-ton floating ship?

100 tons

Buoyant force is greater on a submerged

1kg block of aluminum

A fish normally displaces its own

volume and weight of water (both of these)

Lobsters live on the bottom of the ocean, which means their density is

greater than the density of sea water.

An egg rests at the bottom of a bowl filled with water. When salt is slowly added to the water the egg rises and floats, from which we conclude

salt water is denser than fresh water and salt water is denser than an egg

When you float in fresh water, the buoyant force that acts on you is equal to your weight. When you float higher in the denser water of the Dead Sea, the buoyant force that acts on you is

equal to your weight

When an ice cube in a glass of water melts, the water level

remains the same

When a barrel of water in a rowboat in a swimming pool is poured overboard, the pool level

remains unchanged

A block of wood with a piece of iron tied to the top of it floats in a bucket of water. If the wood and iron are turned over so that the iron is submerged beneath the wood, the water level at the side of the bucket

remains the same

When a load of wood is thrown overboard from a boat in a swimming pool, the pool level

remains unchanged

A hydraulic press multiplies a force by 100, which is done at the expense of

the distance through which the force acts.

The air in your classroom has

mass, weight, energy (all of the above)

In drinking soda or water through a straw, we make use of

atmospheric pressure

Approximately how much air is in a column 1-cm² in cross section that extends from sea level to the top of the atmosphere?

1kg

Marshmallows in a vacuum become

larger

It would be easier to pull the evacuated Magdeburg hemispheres apart if they were

20 km above the ocean surface.

Archimedes' principle applies to

gases, liquids, and fluids (all of the above)

The buoyant force of the atmosphere on a body is equal to the

weight of air displaced

The flight of a blimp best illustrates

Archimedes’ principles

The principle of continuity states that for fluid flow to be continuous it must

speed up in narrow regions of flow and slow down in wide regions of flow (both of these)

Wind blowing over the top of a hill

decreases atmospheric pressure there

The tarp covering on a trailer or truck puffs upward for fast-moving vehicles, which illustrates

Bernoulli’s principle

The Bernoulli effect causes fast-moving vans on the highway to be drawn together when

air speeds up in passing between them

When you blow air between a pair of closely-spaced Ping-Pong balls suspended by strings, the balls will swing

toward each other

An umbrella tends to move upwards on a windy day principally because

air pressure is reduced over the curved top surface.

Sara lies on a bed of sharp nails without harm because

her weight is distributed over hundreds of nails

While standing, your blood pressure is normally greatest in your

feet

Water pressure on a submerged object is greatest against its

bottom

The pressure in a liquid depends on liquid

density and depth (both of these)

Buoyant force acts upward on a submerged object because

pressure against its bottom is greater than pressure against its top.

When holes are drilled through the wall of a water tower, water will spurt out with the greatest speed from the hole closest to

the bottom of the tower

A completely submerged object always displaces its own

volume of fluid

The volume of water displaced by a floating 20-ton boat

is the volume of 20 tons of water

When a boat sails from fresh water to salt water, the boat will float

higher in the water

A scale from which a rock is suspended reads 5 N when the rock is out of water and 3 N when the rock is submerged. Buoyant force on the rock is

2N

Buoyant force is greater on a submerged 1-cubic centimeter block of lead or aluminum?

it’s the same on each

Pumice is a volcanic rock that floats, which means its density is

less than the density of water

Two life preservers have identical volumes, but one is filled with Styrofoam while the other is filled with sand. When the two life preservers are fully submerged, the buoyant force is greater on the one filled with

same on each as long as their volumes are the same

Compared to an empty ship, the same ship loaded with Styrofoam will float

lower in the water

A person floats higher in the dense water of the Dead Sea because

less volume of water is displaced

When scrap iron in a boat is thrown overboard in a swimming pool, the pool level

falls

The pascal is a pressure unit equal to

1 newton per square meter.

To multiply an applied force while using a simple hydraulic lift, your force should be applied to the

small-diameter piston

Atmospheric pressure is caused by the

weight of the atmosphere

when a suction cup sticks to a wall it is

pushed to the wall by the atmosphere

The weight of air in a column 1-m² in cross section that extends from sea level to the top of the atmosphere is

101,000N

When boarding an airplane you bring a bag of chips. While in flight the bag puffs up, because

air pressure in the air-tight bag is greater than cabin air pressure

The buoyant force on a one-ton blimp hovering in air is

one ton

As a fluid gains speed, its internal pressure

decreases

When water is turned on in a shower, the shower curtain moves towards the water spray. This partly involves

pressure changes in moving fluids

A spinning tossed baseball veers off course in the direction of

reduced air pressure on the ball

When you blow air between a pair of closely-spaced Ping-Pong balls suspended by strings, the balls will swing

toward each other

Which temperature scales have equal sized degrees?

celcius and kelvin

In which is the temperature greater? boiling hot tea in a cup or boiling hot tea in fire-engine pail.

both of these are the same

When you touch a hot potato with your finger, energy flows

from the potato to your finger

The amount of heat needed to raise the temperature of 1 gram of water by 1°C is

4.19 Joules

Pour a liter of water at 40°C into a liter of water at 20°C and the final temperature of the two becomes

at or about 30°C

The quantity of heat that a substance can transfer relates to its

mass, specific heat capacity, and change in its temperature (all of the above)

Aluminum has a higher specific heat capacity than iron. This means that for equal masses of aluminum and iron, the metal that heats more quickly when the same amount of heat is applied is

iron

Tomatoes have a higher specific heat capacity than dough. This means that when you bite into a hot pizza

the tomato sauce feels hotter than the dough

A substance that cools down faster than others has a

low specific heat capacity

A substance that heats up relatively quickly has a

low specific heat capacity

Aluminum has a specific heat capacity more than twice that of copper. Place equal masses of aluminum and copper wire in a flame and the one to undergo the fastest increase in temperature will be

copper

One of water's interesting thermal properties is that when heated it takes a relatively

long time in changing temperature

When most substances are heated, molecules inside move faster and take up more space, resulting in thermal

expansion

When an iron ring is heated, the hole becomes

larger

The fact that gasoline overflows a full tank on a hot day is evidence that

gasoline expands more with increasing temperature than its tank

If the temperature of a sample of water at 0°C is slightly increased, its volume

decreases

If the temperature of a sample of water at 4°C is slightly increased, its volume

increases

When water at 4°C is heated it expands. If it is instead cooled it will

also expand

Which of these are good insulators? feathers, wood, or snow

all of the above

Which of these are good conductors? feathers, wood, or snow

none of the above

A block of wood and a block of copper will feel neither hot nor cold to the touch when they each have

your temperatures

In practice, a good insulator.

slows heat flow

If you were caught in freezing weather with only a candle for heat, you would be warmer in

an igloo

Energy transfer by convection is primarily restricted to

fluids (NOT LIQUIDS)

Blow on your hand with your mouth open. Then do the same with your lips puckered and you'll find

a difference in temperatures AND the breath from the puckered lips in cooler

The form of heat transfer that doesn't depend on a medium is

radiation

The pupil of your eye is a net

absorber of radiant energy

The lower the temperature of an object, the

lower the frequency of radiation it emits AND longer the wavelengths it radiates (both of these)

Newton's law of cooling applies to objects undergoing

both cooling and warming

It is commonly thought that a can of beverage will cool faster in the coldest part of a refrigerator. Knowledge of Newton's law of cooling

supports this common knowledge

Which body glows with electromagnetic waves? the sun, the earth, you and your classmates

all of the above

a hot dog pants

to enable evaporation in its mouth and bronchial tract

The surface of hot water has a relatively high rate of

evaporation

We feel uncomfortably warm on a muggy day because water molecules are

condensing on our bodies

Compared with sea-level cooking, in cooking eggs by boiling in mountain regions you should boil the eggs

for a longer time

For increased atmospheric pressure, the boiling point of water

rises

Increased air pressure on the surface of hot water tends to

prevent boiling

An inventor discovers a harmless and tasteless salt, which when added to water changes its boiling point. The market value for this salt will be better if the salt

raises the boiling point of water