Science Litt HWK
acceleration =
(vfinal -vinitial) /t
The Ptolemaic theory of the universe includes
an unmoving earth at the center
warm objects emit predominately which kind of electromagnetic waves?
infrared light
an element with an atomic number of 8
is composed of atoms with only 8 protons
Deep under the sea, one whale calls to another. The wave that travels from the first whale to the second is:
longitudinal
Work of lifting against gravity W=
m x g x h = PE (joules)
Force (two equations) =
ma (newtons), (G x M x m)/d^2
what do you need to calculate the gravitational force between two objects
mass of both objects, gravitational constant, distance between the two objects
If you know PE, g, and height you can figure out
mass of the object with potential energy
what state of salt has the lowest entropy
salt crystals
How does science differ from pseudoscience?
scientific hypotheses can be proven false through experiment
a photon is emitted by an atom when one of the atom's electrons
shifts to a lower energy level
The phenomenon of conduction is generally the favored mode of heat transfer in what type of medium?
solid
it was first discovered that atoms have a nucleus when
some alpha particles were deflected by gold nuclei in rutherford's experiment
Which of the following wave property is the same for all electromagnetic waves moving in vacuum?
speed
the amplitude of a wave is which of the following
starting from the midpoint of its motion, the amplitude is the vertical distance to a wave peak
Copernicus hypothesized that the Universe is built exactly like Ptolemy suggested except:
the Sun is at the center of the universe
What best describes what the temperature of an object measures
the average thermal energy per particle making up the object
if a photon strikes an electron in the ground state in the hydrogen atom
the electron may be boosted to a higher energy if the photon has enough energy
The amount of energy needed to cook an egg is equal to
the energy released if you could uncook the egg
typically, the most important part of an atom involved in chemical bonding is
the outermost electrons
At a given instant, when two identical waves reach the same point and interfere constructively, the waves at the point where they meet experience an upward shift of 10 cm. When those same two waves interfere destructively at another point, what happens at that point?
the point experiences no shift at all
What does power measure
the rate at which work is done
The Second Law of Thermodynamics says which of the following?
the thermal energy of a cool object becomes cooler only if work is done on the object
what is the primary reason your room is more likely to be messy after a period of time than clean?
there are many configurations of items in the room that we would consider "messy" but only a few that we would think of as "neat"
In order to say work has been done on an object, what needs to happen?
there must be a force on the object and the object must move
in a quantum jump where photons are released, which color would have the greatest energy
violet
A fundamental difference between waves and the motion of single objects is:
waves can transfer energy without transferring mass
if you were in a spacecraft moving away from earth would your weight or mass be increasing or decreasing
weight would be decreasing
In which situation would an observer sense electromagnetic waves with a frequency higher than the frequency the source is emitting? a. When the observer is moving away from the source. b. When the observer is moving toward the source. c. When the observer and source are both moving away from each other. d. None of these situations results in the observer seeing a higher frequency.
when the observer is moving towards the source
The voltage across a resistor is 20 V and the current through it is 10 A. What is the resistance of the resistor?
2 Ω
metallic bonds create materials with properties that make them
able to change shape without breaking
A positive electric charge in objects is most commonly achieved by
removing electrons from the orbit
Laws of nature can be characterized by saying that they
represent our best understanding of how the universe works in certain circumstances
The scientific method depends on:
reproducible results
a truck is traveling at 30 m/s and comes to rest in 10 seconds. what is its acceleration
-3 m/s^s
Two electric charges are attracted to each other with a force of 0.080 N. Each charge is halved in value, but they remain in their same relative locations. What is the new force between them?
0.020 N, attractive
A particular electrical appliance requires 30 W. When it is connected to a power source that provides 120 V, the current in the circuit is:
0.25 A
What is the acceleration of a car that reaches a speed of three meters per second from rest in ten seconds?
0.3 meters per second squared
As you lift a 15-kg mass off the ground, you are performing 60 J of work. Considering these facts, how high did you lift the 15 kg? (Note - for this problem use g = 10 m/s2)? And equation used
0.4 m Work done / (9.8 x mass)
What is the frequency of a wave with a speed of 16 m/s and a wavelength of 4 m
4 Hz
distance =
1/2 x acceleration x time^2
KE =
1/2m x v^2
In a closed system, there is 500 J of potential energy and 800 J of kinetic energy and no other forms of energy are present in this system. Ten years later, the kinetic energy is measured at 300 J. After 10 years, the amount of potential energy is:
1000 J
If exactly 8 pounds of oxygen reacts with exactly 1 pound of hydrogen, how many pounds of oxygen would be needed to react with 1.5 pounds of hydrogen?
12 pounds
a rock is propelled upward from the earth with an initial velocity of 60 m/s. it will return to earth in
12 seconds
How much energy does a 200-W light bulb consume in 1 minute? equation
12000 J. Watts x Seconds
If you weigh 150 pounds and are standing on the earth without moving, how much force is the ground exerting on you?
150 pounds
A particular piece of metal requires 80 calories of heat in order to increase its temperature by 10 degrees C. How much heat is needed to increase its temperature by 20 degreesC?
160 calories
When we compare the equations for the force between electric charges and the force between masses, which value is analogous to the quantity 9.00 × 109 Nm2/C2?
6.67 × 10-11 Nm2/kg2
How many bits of information are in a 9-letter word?
72
What is the maximum possible efficiency of a heat engine that operates with a hot reservoir at 1600 K and a cold reservoir at 400 K?
75%
What is the speed of a 1.5-kg mass with a kinetic energy of 48 J?
8 m/s
How many bits of total information appear on a television screen that possessed 3 million pixels?
90 million
what is a polar molecule
A molecule with one side electrically positive and the other side electrically negative.
Aluminum typically gives up three electrons and fluorine typically accepts one electron. If an ionic molecule formed that involved just aluminum and fluorine, what would the formula be?
AIF3
In the analogy of a person climbing and descending a flight of stairs to an electron moving between energy levels, an electron gaining energy would be equivalent to:
going from a lower step to a higher step
Why is it that the lower the electron's orbit, the lower its energy as well?
Electric potential energy decreases the closer two charges get just as in gravity the potential energy is lower when the two masses are closer together.
work =
F x d (joules)
how does a heat engine produce
Heat is converted to work and the excess heat is expelled.
all electromagnetic waves travel at the same speed as
all light waves
Which of the following elements would you most likely mix with silicon in order to make an p-type semiconductor?
aluminum
a changing magnetic field will create what?
an electric fields
definition of a calorie
The amount of heat required to raise the temperature of 1 g of water initially at room temperature by 1 degree C.
what happens to a conductor as we decrease the temperature
The ions in the conductor vibrate less and allow the electrons to pass with less difficulty, therefore the conductivity increases.
Power =
W/t (watts)
Basic research scientists: a. are interested in inquiry for the sake of acquiring fundamental knowledge. b. believe in the healing power of meditation. c. want their research to have practical application to industry or technology. d. often have their discoveries translated into practical uses. e. would be likely to have a patent on a discovery.
a
Most polymers are characterized as:
a collection of small molecules combined into long chains
If you could take an electrically neutral atom of sodium (element 11) and add a proton to its nucleus, you would create which of the following?
a positively charged ion of magnesium (element 12)
metals are held together because of
a sea of electrons
How did Mendeleev organize the periodic table of elements
atomic weight of the element
When we say, "Energy is conserved," we are saying which of the following? a. The energy in a closed system may not change from one kind to another, yet the total amount of energy remain constant. b. The energy in a closed system may change from one kind to another, but the total amount of energy remains constant. c. The energy in a closed system may change from one kind to another, and if so the total amount of energy does not remain constant. d. The energy in a closed system may not change from one kind to another, and the total amount of energy do not remain constant.
b
Which of the following electromagnetic waves has the highest energy? a. The electromagnetic wave with the lowest frequency b. The electromagnetic wave with the highest frequency c. The electromagnetic wave with the longest wavelength d. The electromagnetic wave with the highest speed
b
a silicon semiconductor will transmit electrical current
by electrons and holes
Acceleration due to gravity: a. is a universal constant. b. is a fundamental property. c. decreases with increasing altitude. e. is different for different objects in free fall. f. only occurs on earth.
c
Which of the following is an accurate description of ionic bonding? a. Ions with the same charge come together, adding energy to the system. b. ions with the same charge come together and release energy. c. Oppositely charged ions come to each other and release energy. d. Oppositely charged ions come to each other, adding energy to the system.
c
Which of the following would most significantly affect the amount of kinetic energy in a typical situation? a. Doubling the speed b. Doubling the mass c. Tripling the speed d. Tripling the mass
c
Which statement is true about the discipline of science? a.Science is a complete set of facts about the physical world. b. Science provides answers to all questions about our environment. c. Science provides our best view to the workings of the universe and everything within it. d. Science and intuition are mutually exclusive. e. Science encompasses all of pseudoscience and more.
c
Why is mathematics the language of science? a.Use of mathematics ensures international cooperation among scientists. b. Mathematics separates scientists from non-scientists. c. Mathematics allows scientists to be more accurate in describing an observation of nature. d. Because scientists are more analytical than creative, mathematics is a way to analyze. e. Mathematics is like Latin in that it is a way to communicate that few understand.
c
A battery typically involves which of the following transformations?
chemical potential energy into electric potential energy
What does an electric generator do?
converts mechanical energy into electrical energy and heat
Which of the following is a good conductor? a. rubber b. wood c. plastic d. ocean water e.glass
d
Which phrase describes electrical resistance? a. material through which electrons flow freely b. arrangement of a material's electrons c. potential of a battery with flowing current d. inverse of electrical conduction e. channels for the flow of electrons
d
Semiconductors made with the process of adding a small amount of one substance to another substance and letting the two mix with the silicon are known as __________ semiconductors.
doped
Which of these statements is not true about Copernicus? a. He hypothesized that planetary orbits were circular. b.He thought that Ptolemy's ideas about the shape of orbits were correct. c. He provided the first serious alternative to Ptolemy's system. d. His model of the universe placed the Sun, rather than the Earth, at the center. e. He used telescopic observations to confirm his theories.
e
Which description below best fits for an exothermic reaction?
emits energy into the environment
exothermic and endothermic chemical reactions differ in that
energy is given off only in exothermic reactions
if a chemical bond forms spontaneously then
energy will be released in the reaction
What was Rutherford expecting to see when he performed his gold foil experiment?
essentially all of the alpha particles would show little to no deflection in their trajectories
The property of materials in which magnetic dipoles at the atomic level align with each other is known as which of the following?
ferromagnetism
Newton's three laws of motion include the statement that
for every action there is an equal and opposite reaction
examples of polymers
fur, spider webs, plastic, nylon, cotton, meat
The first person to record observations using a telescope was
galileo galilei
force on earth =
mg (newtons)
Which of the following "parking lot" situations does not violate the Pauli exclusion principle?
no more than one car can fit into a standard parking spot at any given time
Substances that host numerous collisions between electrons that are moving through them have:
non-zero electrical resistance
If the Moon were positioned twice as far from the Earth as it is now, the gravitational attraction would be:
one-fourth as great
Which of the following elements would you most likely mix with silicon in order to make a n-type semiconductor?
phosphorus
The plumbing analogue for resistance is:
pipe diameter
if you cut a bar magnet into two pieces
you get two separate dipole bar magnets
