Physics Chapter 6

One liter of water weighs about 10 N. Suppose a 3-liter container is filled with 266 N of mercury and then lowered into a container of water. Assuming the container is completely submerged, what is the buoyant force acting on it? a. 10 N b. 27 N c. 266 N d. 30 N e. 89 N

D 30 N

If a weighted, air-filled balloon sinks in a lake, it will _____. a. be buoyed up with constant force while sinking b. probably sink to the bottom and probably rise later c. sink until it reaches equilibrium and then remain at constant depth d. always sink to the bottom e. none of the above

D always sink to the bottom

The main difference between gases and liquids is that in a gas _____. a. forces between molecules are larger b. molecules collide more often c. molecules are moving faster d. distances between molecules are larger e. all of the above

D distances between molecules are larger

Water in a tube could be used to make a barometer, but _____. a. It's impossible to make a water barometer b. no glass is strong enough to hold a water barometer c. water would run out of the tube d. the tube would have to be very, very long e. pressure at the tube's bottom would break the tube

D the tube would have to be very, very long

The density of a submerged submarine is about the same as the density of _____. a. iron b. a crab c. a floating submarine d. water e. none of the above

D water

The reason a life jacket helps you float is that _____. a. the jacket makes you weigh less b. the jacket repels water c. the jacket has the same density as an average human d. you and the jacket together have density less than your density alone

D you and the jacket together have density less than your density alone

A hydraulic press works because _____. a. liquids transmit pressure undiminished b. one piston is larger than the other piston c. Pascal's principle is operating d. liquids transmit pressure in all directions e. all of the above

E all of the above

Pascal's principle says that changes in pressure at any point in an enclosed fluid _____. a. quickly diminish from point to point in the fluid b. remain only at the point c. are transmitted only to points close to it d. are transmitted only to points below it e. are transmitted to all points in the fluid

E are transmitted to all points in the fluid

When first put in water, a plastic toy boat will sink until _____. a. the water density equals the density of the boat b. it displaces a volume of water equal to its own volume c. the buoyant force equals the density of the boat d. the buoyant force equals the volume of the boat e. it displaces a weight of water equal to its own weight

E it displaces a weight of water equal to its own weight

An immersed object is buoyed up by a force equal to the volume of the fluid it displaces. True False

False

Archimedes' principle says that whenever you change the pressure in one part of a fluid, this change is transmitted to other parts of the fluid. True False

False

Because concrete is much denser than water, a ship made of concrete won't float. True False

False

Pressure in a fluid is inversely proportional to the depth at which the pressure measurement is taken. True False

False

Pressure in a liquid depends on the direction the pressure gauge is pointing. True False

False

The buoyant force on a submerged rock is equal to its weight in the water. True False

False

A fish moves up or down in water by changing its average density. True False

True

An object will sink in water if its density is greater than the density of water. True False

True

The buoyant force on a submerged rock depends on the volume of the rock. True False

True

The reason objects immersed in a fluid experience an upward buoyant force is because fluid pressure on the bottom of the object is greater than fluid pressure on the top of the object. a. True b. False

True

The upward force that a liquid exerts on a submerged or partly submerged object is called buoyant force. True False

True

The weight of fluid displaced by a floating object is equal to the weight of the object. True False

True

Pressure in a liquid depends on the _____. a. depth of the measuring point b. mass of the liquid c. volume of the liquid d. density of the liquid e. both A and D

e. both A and D

Atmospheric pressure at sea level is about _____. a. 100 kP b. 20 kP c. 10 P d. 100 P e. 10 kP

A 100 kP

A 40,000-N car is lifted on a hydraulic piston of area 1000 square centimeters. How much force on a 10 square-centimeter piston is needed to lift the car? a. 400 b. 8,000 N c. 10,000 N d. 4,000 N e. 40,000 N

A 400

Which has the larger buoyant force, a balloon filled with helium or a balloon the same size filled with air? a. Neither — they both experience the same buoyant force. b. The air balloon c. The helium balloon

A Neither — they both experience the same buoyant force.

Which has more weight, a balloon filled with helium or a balloon the same size filled with air? a. The air balloon b. The helium balloon c. Neither — they both have the same weight.

A The air balloon

A floating ice cube contains a small piece of iron. After the ice cube melts, the water level will _____. a. fall b. remain unchanged c. rise

A fall

If you are standing on the moon and release a balloon filled with helium gas, the balloon will _____. a. fall b. neither rise nor fall c. rise

A fall

When you float in salt water compared to floating in fresh water, the buoyant force that supports you is _____. a. the same b. less c. greater

A greater

A block of balsa wood floats on water while a block of lead the same size lies submerged in the water. The buoyant force is _____. a. greater on the lead b. the same for both c. greater on the wood

A greater on the lead

Lobsters live on the bottom of the ocean. The density of a lobster is _____. a. greater than the density of seawater b. equal to the density of seawater c. less than the density of seawater

A greater than the density of seawater

The volume of water displaced by a floating 20,000-N boat _____. a. is the volume of 20,000 N of water b. is 20,000 cubic meters c. depends on the shape of the ship's hull d. is the volume of the boat

A is the volume of 20,000 N of water

Compared to an empty ship, the same ship loaded with plastic foam will float _____. a. lower in the water b. at the same level in the water c. higher in the water

A lower in the water

If an object has a density greater than the density of water, it will _____. a. sink b. neither float nor sink, but stay anywhere it is put c. float

A sink

A hydraulic arrangement consists of a water-filled U-tube that is wider on one end than on the other. Pistons are fitted in both ends. To multiply an input force, the input end should be the one having the _____. a. smaller... b. It doesn't matter what relative size the piston is. c. larger-diameter piston

A smaller...

One barometer tube has twice the cross-sectional area of another. Mercury in the smaller tube will rise _____. a. the same height as in the larger tube b. four times as high as mercury in the larger tube c. twice as high as mercury in the larger tube d. more than four times as high as in the larger tube e. none of the above

A the same height as in the larger tube

The pressure at the bottom of a jug filled with water does NOT depend on the _____. a. surface area of the water b. density of water c. depth of the liquid d. acceleration due to gravity e. none of the above

A the surface area

Archimedes' principle says that an object is buoyed up by a force that is equal to the _____. a. weight of the fluid displaced b. mass of the fluid displaced c. volume of the fluid displaced d. mass of the object e. none of the above

A weight of the fluid displaced

About how high can water theoretically be lifted by a vacuum pump at sea level? a. More than 10.3 m b. 10.3 m c. Less than 10.3 m

B 10.3 m

In a hydraulic device, the output piston has 100 times the cross-section area as the input piston. This means the device will multiply force _____. a. 1000 times b. 100 times c. 10 times d. none of the above

B 100 times

Floating Freda, who can just barely float in fresh water, has a mass of 44 kg. Her volume is therefore about _____. a. 22 liters b. 44 liters c. 220 liters d. none of the above

B 44 liters

An industrial container holds 100 N of water. The area of the inside bottom of the container is 2 square meters. What pressure does the water exert on the bottom of the container? a. 0.02 N per square meter b. 50 N per square meter c. 100 N per square meter d. 400 N per square meter e. none of the above

B 50 N per square meter

Water pressure on a submerged object is greatest against the _____. a. corners of the object b. bottom of the object c. sides of the object d. top of the object e. none of the above

B bottom of the object

In a vacuum on Earth, an object has no _____. a. temperature b. buoyant force c. weight d. heat e. mass

B buoyant force

A kilogram of lead and a kilogram of aluminum are submerged in water. The buoyant force is _____. a. greater on the lead b. greater on the aluminum c. the same for both

B greater on the aluminum

If an object has a density equal to the density of water, it will _____. a. sink b. neither float nor sink, but stay anywhere it is put c. float

B neither float nor sink, but stay anywhere it is put

The buoyant force on an object is least when the object is _____. a. submerged near the bottom b. partly submerged c. submerged near the surface d. none of the above

B partly submerged

A boat loaded with a barrel of water floats in a swimming pool. When the water in the barrel is poured overboard, the swimming pool level will _____. a. fall b. remain unchanged c. rise

B remain unchanged

When an ice cube in a glass of water melts, the water level _____. a. falls b. remains the same c. rises

B remains the same

An egg is placed at the bottom of a bowl filled with water. Salt is slowly added to the water until the egg rises and floats. From this experiment, one can conclude that _____. a. buoyant forces do not always act upward b. the density of salt water exceeds the density of the egg c. salt sinks to the bottom d. calcium in the eggshell is repelled by sodium chloride e. none of the above

B the density of salt water exceeds the density of the egg

Suppose a stone weighs 8 N in the air, but in water it weighs only 5 N. What is the buoyant force acting on the stone? a. 13 N b. 5 N c. 3 N d. 16 N e. 8 N

C 3 N

Where is the buoyant force on a submerged rock greater, near the surface of the fluid or 10 m below the surface? a. Near the surface b. 10 m below the surface c. Neither place—the buoyant force is independent of depth

C Neither place- the buoyant force is independent of depth

Where is the pressure greater, one meter beneath the surface of Lake Michigan or one meter beneath the surface of a swimming pond? a. In the pond b. In Lake Michigan c. The pressure is approximately the same in both places

C The pressure is approximately the same in both places

Compared to the buoyant force of the atmosphere on a 1-kilogram helium-filled balloon, the buoyant force of the atmosphere on a nearby 1-kilogram solid iron block is _____. a. considerably more b. the same c. considerably less

C considerably less

In a hydraulic press operation, it is impossible for the _____. a. none of the above b. force output to exceed the force input c. energy output to exceed the energy input d. output displacement to exceed the input displacement

C energy output to exceed the energy input

Two equal-sized buckets are filled to the top with water. One of the buckets has a piece of wood floating in it, making its total weight _____. a. less than the weight of the other bucket b. more than the weight of the other bucket c. equal to the weight of the other bucket

C equal to the weight of the other bucket

When a boat sails from fresh water to salt water, the boat will float _____. a. at the same level b. lower in the salt water c. higher in the salt water

C higher in the salt water

If the part of an iceberg that extends above the water were removed, the _____. a. density of the iceberg would change b. iceberg would sink c. iceberg would rise d. pressure on the bottom of the iceberg would increase e. none of the above

C iceberg would rise

Alcohol is less dense than water. If alcohol is used to make a barometer on a day when atmospheric pressure is normal, the level of the alcohol will be _____. a. 10.3 m b. less than 10.3 m c. more than 10.3 m

C more than 10.3 m

An ice cube floating in a glass of water contains many air bubbles. When the ice melts, the water level will _____. a. rise b. fall c. remain unchanged

C remain unchanged

A barometer that uses water instead of mercury will be _____. a. shorter b. the same height c. taller

C taller

The reason an iron ship doesn't sink is that _____. a. an iron ship will always sink b. air inside decreases it's weight c. the iron displaces more water than it would if it were in a solid block d. iron is less dense than water

C the iron displaces more water than it would if it were in a solid block

Compared to the buoyant force of the atmosphere on a 1-liter helium-filled balloon, the buoyant force of the atmosphere on a nearby 1-liter solid iron block is _____. a. considerably less b. considerably more c. the same

C the same

A balloon is buoyed up with a force equal to the _____. a. atmospheric pressure b. density of surrounding air c. weight of air it displaces d. weight of the balloon and contents e. all of the above

C weight of air it displaces

A 2-ton dirigible hovers in the air. The buoyant force acting on it is a. zero. b. less than 2 tons c. more than 2 tons d. 2 tons

D 2 tons