Deck 13: Liquids

Question 1

The concept of pressure involves both

A)force and volume.
B)force and area.
C)area and volume.

Answer 1

force and area.

Question 2

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

A)water is denser at deeper levels.
B)water pressure increases with depth.
C)surface tension exists only on the surface of liquids.
D)it looks better.
E)none of the above

Answer 2

water pressure increases with depth.

Question 3

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

A)partly submerged.
B)submerged near the surface.
C)submerged near the bottom.
D)none of the above

Answer 3

partly submerged.

Question 4

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

A)the bottom of the tower.
B)the middle of the tower.
C)the top of the tower.
D)all the same

Question 5

Sara lies on a bed of sharp nails without harm because

A)many of the nails don't make contact with her body.
B)her weight is distributed over hundreds of nails.
C)she exercises mind over matter.
D)none of the above

Question 6

Which will remain the same for two identical books, one lying flat and the other standing on an end?

A)weight
B)pressure
C)both of these
D)neither of these

Question 7

The pressure at the bottom of a jug filled with water does NOT depend on

A)the acceleration due to gravity.
B)water density.
C)the height of the liquid.
D)surface area of the water.
E)none of the above

Question 8

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

A)less than 10 tons.
B)10 tons.
C)more than 10 tons.
D)depends on density of sea water

Question 9

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

A)firm mattress.
B)soft mattress.
C)water bed.
D)none of these will help.

Question 10

The least buoyant force on a rock is when it is submerged

A)near the surface.
B)halfway to the bottom.
C)near the bottom.
D)none of the above

Question 11

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

A)is 20 cubic meters.
B)is the volume of 20 tons of water.
C)is the volume of the boat.
D)depends on the shape of the ship's hull.
E)none of the above

Question 12

While standing, your blood pressure is normally greatest in your

A)head.
B)heart.
C)feet.
D)same in each

Question 13

A completely submerged object always displaces its own

A)volume of fluid.
B)weight of fluid.
C)density of fluid.
D)all of the above
E)none of the above

Question 14

The pressure in a liquid depends on liquid

A)density.
B)depth.
C)both of these
D)neither of these

Question 15

The mass of a cubic meter of water is

A)1 kg.
B)10 kg.
C)100 kg.
D)1000 kg.
E)9800 N.

Question 16

One liter of water has a mass of

A)1 kilogram.
B)14.7 grams.
C)500 grams.
D)none of the above

Question 17

There is a legend of a Dutch boy who bravely held back the Atlantic Ocean by plugging a leak near the top of a dike with his finger until help arrived. Which is the more likely scenario?

A)the huge size of the Atlantic Ocean makes this impossible
B)although the force on his finger would have been huge, the pressure would have been small enough for this to occur
C)the force on his finger would have been less than 1 N
D)both force and pressure on his finger would have been great, but not too great for a public-spirited Dutch lad
E)none of the above

Question 18

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

A)half.
B)the same as with both feet.
C)doubled.
D)none of the above

Question 19

Buoyant force acts upward on a submerged object because

A)it acts in a direction to oppose gravity.
B)the weight of fluid displaced reacts with an upward force.
C)pressure against its bottom is greater than pressure against its top.
D)none of the above

Question 20

Water pressure on a submerged object is greatest against its

A)top.
B)bottom.
C)sides.
D)same against all surfaces
E)none of the above

Question 21

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

A)salt water is denser than fresh water.
B)salt water is denser than an egg.
C)both of these
D)neither of these

Question 22

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

A)lower in the water.
B)higher in the water.
C)at the same water level.

Question 23

The density of a submerged submarine at rest is about the same as the density of

A)a crab.
B)iron.
C)a floating submarine.
D)water.
E)none of the above

Question 24

Buoyant force is greater on a submerged 1-cubic centimeter block of

A)lead.
B)aluminum.
C)same on each

Question 25

Compared to the density of water, the density of a fish is

A)more.
B)less.
C)the same.

Question 26

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

A)less than the density of water.
B)equal to the density of water.
C)more than the density of water.
D)need more information.

Question 27

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

A)Styrofoam.
B)sand.
C)same on each as long as their volumes are the same

Question 28

The reason a life jacket helps keep you afloat is

A)the jacket makes you weigh less.
B)the jacket has the same density as an average human.
C)the jacket repels water.
D)if you sink, the jacket sinks.
E)the density of both you and the jacket together is less than your density alone.

Question 29

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

A)2 N.
B)3 N.
C)4 N.
D)5 N.

Question 30

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

A)greater than the density of sea water.
B)equal to the density of sea water.
C)less than the density of sea water.

Question 31

Ice cubes submerged at the bottom of a liquid indicate that the liquid

A)produces insufficient buoyant force on the ice.
B)is warmer than the ice.
C)is only partly displaced by the submerged ice.
D)is less dense than ice.

Question 32

Buoyant force is greater on a submerged

A)1-kg block of lead.
B)1-kg block of aluminum.
C)is the same on each

Question 33

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

A)lead.
B)Styrofoam.
C)same for both

Question 34

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

A)less than 100 tons
B)100 tons
C)more than 100 tons
D)100 cubic meters
E)depends on the ship's shape

Question 35

A lobster crawls onto a bathroom scale on the ocean floor. Its weight compared to its weight above the surface is

A)greater.
B)less.
C)the same.

Question 36

A 5-N block of wood is difficult to fully submerge in a pool of mercury because the buoyant force on the block when submerged is

A)less than 5 N.
B)5 N.
C)much more than 5 N.

Question 37

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

A)by a force equal to its own weight.
B)by a force equal to the weight of liquid displaced.
C)and floats in accord with Archimedes' principle.
D)all of the above
E)none of the above

Question 38

Buoyant force is greater on a submerged 10-newton block of

A)lead.
B)aluminum.
C)same on each

Question 39

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. The density of the rock is

A)the density of water.
B)1.5 times the density of water.
C)2.5 times the density of water.
D)3.5 times the density of water.
E)none of the above

Question 40

A fish normally displaces its own

A)volume of water.
B)weight of water.
C)both of these
D)neither of these

Question 41

Two life preservers have identical volumes, one filled with Styrofoam and the other filled with sand. When the two life preservers are worn by swimmers, one swimmer floats with part of the preserver above water, and the other swimmer sinks. In this case the buoyant force is greater on the life preserver filled with

A)Styrofoam.
B)sand.
C)same for both

Question 42

The fact that the weight of a brim-full container of water is unchanged whether or not something floats in it is nicely employed in

A)hydraulic devices.
B)all floating devices.
C)Scotland's Falkirk Wheel.
D)none of the above

Question 43

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

A)rises.
B)falls.
C)remains the same.

Question 44

A floating ice cube contains small pieces of iron. The water level after melting will

A)rise.
B)fall.
C)remain unchanged.

Question 45

An ice cube with large air bubbles in it floats in a brim-full container of water. When the ice cube melts,

A)water spills over.
B)no change in water level occurs.
C)water level in the container goes down.

Question 46

If you float a piece of wood in a container half-full of water that rests on a weighing scale, the weight reading on the scale will

A)decrease.
B)remain unchanged.
C)increase.

Question 47

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

A)rises.
B)falls.
C)remains unchanged.

Question 48

A key feature of the Falkirk Wheel in Scotland is that opposite gondolas have the same weight when both are brim-full of water

A)and boats in each have about equal weights.
B)and at least one boat is in each gondola.
C)regardless of the weights of boats or no boats in each.
D)none of the above

Question 49

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

A)less volume of water is displaced.
B)more volume of water is displaced.
C)of a greater buoyant force.

Question 50

The amount of water displaced by a liter-sized block of ordinary wood floating in water is

A)less than 1 liter.
B)1 liter.
C)more than 1 liter.
D)depends on the water density
E)none of the above

Question 51

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

A)higher in the water.
B)lower in the water.
C)at the same level in the water.

Question 52

A large ice cube containing an iron railroad spike floats in a brim-full container of water. When the ice cube melts,

A)water spills over.
B)no change in water level occurs.
C)water level in the container drops.

Question 53

If you float a piece of wood in a container brim-full of water that rests on a weighing scale, some water will spill. Then the weight reading on the scale will

A)decrease.
B)remain unchanged.
C)increase.

Question 54

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.

Question 55

A mountain that floats on the mantle indicates that the density of the mantle is

A)less than that of the mountain.
B)about the same as that of the mountain.
C)greater than that of the mountain.
D)none of the above

Question 56

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

A)rises.
B)falls.
C)remains unchanged.

Question 57

A heavy iron ball is placed in an aluminum pie pan that floats in a bucket. The water level at the side of the bucket is marked. Then the ball is removed and allowed to sink in the bucket. The water line at the side of the bucket

A)goes down.
B)is the same.
C)rises.

Question 58

An important condition for operation of the Falkirk Wheel is that

A)water in each gondola have the same depth.
B)ships carried are more or less equal in weight.
C)no water spill when a ship enters a gondola.
D)all of the above
E)none of the above

Question 59

When a large floating ice cube with unfrozen water inside melts, the water level in its container

A)goes down.
B)remains unchanged.
C)goes up.

Question 60

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

A)greater than your weight.
B)less than your weight.
C)equal to your weight.

Question 61

In a hydraulic-press operation, it is impossible for the

A)output displacement to exceed the input displacement.
B)force output to exceed the force input.
C)energy output to exceed the energy input.
D)output piston's speed to exceed the input piston's speed.
E)none of the above

Question 62

Surface tension is a direct result of

A)viscosity.
B)Archimedes' principle.
C)adhesive forces between molecules in a liquid or solid.
D)cohesive forces between molecules in a liquid.

Question 63

Pascal's principle applies to

A)liquids.
B)gases.
C)both of these
D)none of these

Question 64

If a battleship sinks in a canal lock, the water level in the lock will

A)rise.
B)fall.
C)remain unchanged.

Question 65

If a weighted air-filled balloon sinks in deep water, it will

A)likely sink to an equilibrium level before reaching bottom.
B)likely burst if water pressure is great enough.
C)be acted on by a continuously decreasing buoyant force.
D)none of the above

Question 66

When you place a stick in water and remove it, the stick is wet. If you instead place it in mercury the opposite occurs. The stick is dry. This is because adhesive forces are greater

A)between stick and water.
B)between the stick and mercury.
C)between the mercury and the water.
D)none of the above

Question 67

Surface tension of liquids

A)increases when wetting agents are added.
B)decreases as the liquid temperature increases.
C)is about the same for all liquids.
D)results from a thin molecular membrane beneath the liquid surface.
E)keeps steel ships afloat.

Question 68

A consequence of surface tension for water is

A)capillary action.
B)wet sand being firmer than dry sand.
C)the different tastes of hot and cold oily soup.
D)all of the above
E)none of the above

Question 69

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

A)rises.
B)falls.
C)remains the same.

Question 70

The pascal is a pressure unit equal to

A)1 newton per square meter.
B)1 kilogram per square meter.
C)1 newton per square centimeter.
D)1 kilogram per square centimeter.

Question 71

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

A)large-diameter piston.
B)small-diameter piston.
C)relative piston sizes don't matter.

Question 72

A very lightweight horizontal loop of wire is suspended from a fine spring, lowered into water, and then raised to the surface. Any further attempt to raise it causes the spring to

A)stretch.
B)contract.
C)stay the same.

Question 73

The attraction between like substances, stickiness, is called

A)adhesion.
B)cohesion.
C)depends on the substances.

Question 74

When you observe the applications of pistons in lifting operations you're seeing

A)Pascal's principle in action.
B)how energy can be increased.
C)both of these
D)neither of these

Question 75

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

A)energy, which is divided by 100.
B)the distance through which the force acts.
C)the time through which the force acts.
D)the mechanism providing the force.
E)none of the above

Question 76

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

A)rises.
B)falls.
C)remains unchanged.

Question 77

The attraction between unlike substances is called

A)adhesion.
B)cohesion.
C)depends on the substances.

Question 78

If the part of an iceberg that extends above the water were suddenly removed, the

A)iceberg would sink.
B)buoyant force on the iceberg would decrease.
C)density of the iceberg would change.
D)pressure on the bottom of the iceberg would increase.
E)none of the above