Test 3

The planet earth loses heat mainly by

radiation

**If 50 Newtons of force is added over a liquid with 1 m2 of surface area surface area, how many Newtons of weight can be lifted by a hydraulic piston with a surface area of .01 m2?

**Not 50 N

**Which has the most pressure at the bottom?

**Not a tube of water 20 m deep with a diameter of 1 cm

What is the approximate mass of a 1-square-centimeter column of air that extends from sea level to the top of the atmosphere?

1 kilogram

The fact that desert sand is very hot in the day and very cold at night is evidence that sand has

a low specific heat

The smallest particle of those listed below is

a quark

The pressure in a liquid depends on liquid

density and depth

Warm air rises because faster moving molecules tend to move to regions of less

density and less pressure

Which of the following expands most when the temperature is increased? Equal volumes of

helium

The moderate temperatures of islands throughout the world has much to do with waters

high specific heat

The most common state of matter in the universe is

plasma

Both black and white road surfaces absorb sunlight. At the end of a sunny day the warmer road surface will be

the black surface

The reason a life jacket helps you float is

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

How many different elements are in a water molecule?

two

Which of these atoms has the most mass?

uranium

The pressure at the deepest point of a lake 10 m deep is about

100,000 N/m^2

The mass of a cubic meter of water is

1000 kg

Before ice can form on a lake, all the water in the lake must be cooled to

4 degrees C

Which of these statements is true?

Atoms are the smallest subdivision of matter that retains the chemical properties of a substance.

The air in the room has

all of these mass, weight, energy

The technology for orbiting solar power plants

already exists

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

atmospheric pressure

A bubble of air released from the bottom of a lake

becomes larger as it rises

Which body glows with electromagnetic waves?

both the sun and earth

Water pressure is greatest against the

bottom of the object

The attraction between molecules of the same kind is called

cohesion

When a bimetallic bar made of copper and iron strips is heated, the bar bends toward the iron strip. The reason for this is

copper expands more than iron

A force that determines the chemical properties of an atom is

electrical force

If water flows into a smaller diameter pipe and speeds up, the bubbles in the water

expand

Energy transfer by convection is primarily restricted to

fluids

When you touch a cold piece of ice with your finger, energy flows

from your finger to the ice

An object will normally be a net radiator of energy when its temperature is

higher than its suroundings

Which of the following normally warms up fastest when heat is applied?

iron

Your feet feel warmer on a rug than on a tile floor because a rug

is a better insulator than tile

Heat is measured in units of

joules and calories

When an iron ring is heated, the hole becomes

larger

As a helium-filled balloon rises in the air, it becomes

less dense

Metals are both good heat conductors and good electrical conductors because of the

looseness of outer electrons in metal atoms

A substance that heats up relatively quickly has a

low specific heat

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

lower in the water

About what percentage of the molecules that make up the atmosphere are below an aircraft that flies at an altitude of 6 kilometers?

more than 50%

Which of the following is not a mixture?

none. all of the above are mixtures

What makes an element distinct?

number of protons

A one-ton blimp hovers in the air. The buoyant force acting on it is

one ton

In our part of the universe, antimatter is

short-lived

If you are standing in a cave on a cliff, and the air outside the cave is moving much faster than the air inside the cave,

the pressure difference wants to push you out of the cave

The higher the temperature of an object

the shorter the wavelengths it radiates

Atoms heavier than helium were made by

thermonuclear fusion

A completely submerged object always displaces its own

volume of fluid

A balloon is buoyed up with a force equal to the

weight of air it displaces