College Physics 13 + 14

Water pressure is greatest against the

bottom of a submerged object

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

water pressure is greater with increasing depth

The pressure in a liquid depends on liquid

both of these (density and depth)

One liter of water has a mass of

1 kilogram

Blood pressure is normally greater in your

feet

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

10 tons

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

The mass of a cubic meter of water is

1000 kg

Pumice is a volcanic rock that floats. Its density is

less than the density of water

The reason that buoyant force acts upward on a submerged object is that

upward pressure against the bottom is greater than downward pressure against the top of the submerged object

A completely submerged object always displaces its own

volume of fluid

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

the same

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

partly submerged

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

buoyant force does not depend on depth

The reason a life jacket helps you float is

the density of both you and the jacket together is less than your density alone

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

the bottom of the tower

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

water

A floating ice cube contains small pieces of iron. During melting the water level will

fall

The pascal is a pressure unit equal to one

newton per square meter

To multiply the input force of a hydraulic lift, the input end should be the one having the

smaller diameter piston

The ratio of output force to input force of a hydraulic press will be equal to the ratio of the output and input piston

areas

A hydraulic press multiplies a force by 100. This multiplication is done at the expense of

the distance through which the force acts

A consequence of the surface tension of water is

all of these

Surface tension is a direct result of

cohesive forces between molecules in a liquid

Surface tension of liquids

decreases as the liquid temperature increases

A large block of wood and a smaller block of iron on weighing scales both register 1 ton. Taking buoyancy of air into account, which has the greater mass?

wood

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

atmospheric pressure

At normal atmospheric pressure and temperature, 1 cubic meter of air has a mass of about

1\.25 kg

Marshmallows in a vacuum become

larger

About how high can water at sea level be theoretically lifted by a vacuum pump?

10\.3 m

When a suction cup sticks to a wall it is

pushed to the wall by the atmosphere

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

pressure changes in moving fluids

The Bernoulli effect causes passing ships to be drawn together when the ships are close and moving in

either the same or opposite directions (either of these)

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

Bernoulli’s principle

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

both of these (speed and slow down)

As fluid gains speed, its internal pressure flow

decreases

When a gas in a container is squeezed to half its volume with no change in temperature, the gas pressure

doubles

When a gas in a container is squeezed to half its volume, its density

doubles

When a gas in a container expands to twice its volume, its density

halves

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

A swimmer cannot snorkel more than a meter deep because air

at the surface will not freely enter the higher pressure region in the compressed lungs

A bubble of air released from the bottom of a lake

becomes larger as it rises

A scuba diver losing her air supply while far beneath the water surface is advised when ascending to

allow air to escape her lungs

An empty jar is pushed open-side downward into water so that trapped air cannot escape. As it is pushed deeper, the buoyant force on the jar

decreases

Archimedes’ principle applies to

all of these

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’ principle

An object in a vacuum has no

buoyant force

A car with closed windows makes a left hand turn. a helium-filled balloon in the car moves to the

left

Compared with air pressure on the outside, air pressure inside an inflated stretched balloon is

greater

Atmospheric molecules do not fly off into outer space due to

Earth gravitation cohesive forces

Atmospheric pressure is caused by the

weight of the atmosphere

The air in your classroom has

all the above

About what percentage of molecules in the air make up the atmosphere below a 6-kilometer altitude?

more than 50%

The energy source responsible for molecular motions in Earth’s atmosphere is

the sun