Exam 3

Question 1

the density of a 2-cubic meter block of mass of 600 kg is

Answer 1

300 kg/m3

Question 2

airplane flight best illustrates

Answer 2

Bernoulli’s principle

Question 3

in the early 1800 Robert Brown made an observation that advanced the atomic hypothesis. What was the observation?

Answer 3

jiggling of dust particles which was interpreted as particles being struck unequally in different sides by unseen molecules

Question 4

an element is distinct because of its number of

Answer 4

protons

Question 5

If sodium atom loses an electron from its electron cloud, the resulting atom is

Answer 5

a sodium ion

Question 6

a spring is stretched 10 cm by a suspended 1-kg block. If two springs side-by-side are sued to suspend the 3-kg block, each spring will then stretch

Answer 6

15 cm

Question 7

one neutron added to helium nucleus results in

Answer 7

beryllium

Question 8

where do naturally occurring elements heavier than boron come from?

Answer 8

they are made by stars in nuclear fusion and supernova events

Question 9

how does one isotope differ from another?

Answer 9

it has a different number of neutrons

Question 10

which of these atoms has the largest number of protons in the nucleus?

Answer 10

neon

Question 11

consider a mouse and an elephant. which is stronger, and which is stronger scaled proportionally for its weight?

Answer 11

an elephant is stronger, but a mouse is stronger scaled proportionally for its weight

Question 12

the air of the atmosphere is best described as

Answer 12

a mixture

Question 13

how does the arrangement of atoms in a crystalline substance differ from the arrangement in a noncrystalline substance?

Answer 13

atoms in crystals are in ordered array with long range order. In amorphous materials, they have only short range order

Question 14

which of these particles has the least mass?

Answer 14

electron

Question 15

are most of the atoms around us here on earth younger or older than the sun?

Answer 15

most are older than the sun

Question 16

the volume of an atom is due mostly to its

Answer 16

electron clouds

Question 17

an important feature of the electrons that are in the electron shells about the nucleus of an atom is

Answer 17

that these electrons have wave properties

Question 18

an object is fully submerged in water. the buoyant force on the object is equal to

Answer 18

the weight of the water that the submerged object displaces

Question 19

the water is poured out of a 1-liter jug, the lid replaced and the empty jug submerged in water. which of the following is true about the buoyant force? Remember 1 liter of water has a mass of 1 kilogram

Answer 19

the buoyant force is about 10 N

Question 20

compared to a bar of pure gold, the density of a pure gold ring is

Answer 20

the same

Question 21

when subjected to a deforming force, we find that play dough is far more elastic than an aluminum rod would be

Answer 21

false

Question 22

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

Answer 22

higher in the water

Question 23

since the atoms are mostly empty space, why don’t we fall through a floor we stand on?

Answer 23

electrons in one atom repel the electrons in another

Question 24

that volume occupied by a gas is reduced by half while the temperature remains constant. we will now find that

Answer 24

the pressure is double

Question 25

buoyant force acts upward on a submerged object because

Answer 25

pressure from the liquid against the bottom of the object is greater than pressure against its top

Question 26

a pair of hydrogen nuclei fused together produces

Answer 26

helium

Question 27

what does the atomic number of an element tell you about the element?

Answer 27

the number of protons in its nucleus

Question 28

which of the following is NOT true in regard to the surface tension of water

Answer 28

is responsible for buoyancy

Question 29

why cant atoms be seen with a powerful optical microscope?

Answer 29

atoms are much smaller than a wavelength of light

Question 30

which of the following is TRUE about drinking water from a straw

Answer 30

air pressure pushes water up the straw so straws can only be most 10.3 in height

Question 31

consider several roped all made of the same type of fibers. in general the strongest rope will be the one

Answer 31

with the greatest cross sectional area

Question 32

the discovery of the Higgs boson will likely

Answer 32

change our idea of what it means for matter to have mass

Question 33

the cosmos is comprised mostly of

Answer 33

dark energy and dark matter

Question 34

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

Answer 34

20 km above the ocean

Question 35

If you had a penny for every atom in a penny, how much money would you have?

Answer 35

enough to give every person on the planet 40 billion dollars

Question 36

when the curve of an arch matches the inverted image of drooping chain held at both ends, the curve is called a

Answer 36

catenary

Question 37

which of the following is true about nucleons?

Answer 37

they are made of quarks

Question 38

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

Answer 38

is the volume of 20 tons of water

Question 39

which of the following is NOT true?

Answer 39

the buoyant force on a fully submerged object depends upon the depth. the deeper the object the greater the buoyant force

Question 40

as a balloon rises higher and higher into the atmosphere its

Answer 40

volume increases