physics and human affairs final uark
Suppose that the force of gravity between the sun and Earth suddenly stopped operating. What would happen?
Earth would move straight ahead, in a straight line, rather than orbiting the sun
Object A has an electric charge that is 10 times larger than the charge on object B. When placed near each other, how does the force by A on B compare with the force by B on A?
They are equal.
A "wave" could best be defined as
a transfer of molecules from one point to another along the direction of motion, where the molecules are bunched into groups.
The main point of Newton's law of motion is that forces cause
acceleration
Galileo's principle of falling is limited by the condition that
air resistance must be negligible
In an electrical circuit, the number of "amperes" measures the
amount of electric current flowing around the circuit.
An "ion" is
an atom with an excess or deficiency of electrons.
If you rub a transparency sheet with tissue and then hold the transparency sheet and the tissue at rest a short distance apart, they will then exert
an attractive electric force on each other, but no magnetic force.
A proton is maintained at rest in the middle of a box that has no matter inside it other than the single proton. Assuming that the box is isolated from all external influences, which of the following would we expect to find at some other point X inside the box?
an electric field
In the case of light waves, the thing doing the "waving" is
an electromagnetic field.
While a rock is falling straight down with negligible air resistance, it has
an increasing speed
All magnetic forces are produced by
charges in motion.
If two electrons are at rest a short distance apart, the electromagnetic forces they exert on each other will be
electric but not magnetic
A book is given a brief shove along a table top and released so that it slides a short distance and comes to rest. According to Aristotle, it stopped because
its natural motion is to come to rest
The "energy efficiency" of a device is
its useful energy output divided by the total energy put into the device.
In comparing two waves of the same type and same amplitude, the one with the longer wavelength would have
lower frequency.
The figure represents a multiple-flash photo of two balls moving to the right, and shows both balls at several numbered times. In the figure,
neither ball is accelerated, and the lower ball is moving fastest
A bicyclist moves around a circular track at a constant [or unchanging] speed. The bicyclist has
non-zero velocity and non-zero acceleration
A 10 kg meteor moves through outer space, far from all gravitational influences. How much work is done on the meteor during a 5 m segment of its path?
none
Which of the following is an example of a true "wave", as that word is used in physics?
none of the above
A battery's "voltage" is
the amount of energy it gives to each coulomb of electrical charge.
A system's "entropy" is
the amount of microscopic disorganization in the system.
In Ptolemy's theory, retrograde planetary motion is explained as
the backward part of the planet's loop-the-loop orbits around Earth.
"Energy" could best be defined as
the capacity to do work.
According to the second law of thermodynamics,
the entropy of all the participants in any physical process cannot decrease.
"Physics" could best be described as the study of
the general principles underlying natural phenomena.
Meteors in outer space keep moving, rather than slowing down and stopping. This behavior is predicted by
the law of inertia
Historically, the earliest atomic model to explain electrical phenomena was
the planetary model.
The filament of a lightbulb glows, while the connecting wires do not. This is because
the resistance is larger in the lightbulb than in the wires.
The biggest reason why heat engines are far from 100% efficient is
the second law of thermodynamics
One piece of evidence that Democritus found for his idea that everything is made of atoms was
the smell of bread and of other substances
Suppose you are on the moon and you drop a rock and a feather at the same time. You will find that
the two fall at the same speed, but this speed is slower than a rock would fall on Earth
Which of the following best describes the meaning of "force"?
A body exerts a force on another body when the first body causes the second body to accelerate
A satellite orbits the earth at an unchanging speed of 18,000 mph. This satellite
-is accelerated. -has a changing velocity
According to the second law of thermodynamics,
-thermal energy flows spontaneously from hot objects to cold objects. -the total entropy of all the participants in any physical process cannot decrease. -energy process that uses thermal energy to do work must have a thermal energy exhaust.
Which one [or ones] of the following is a possible final state for a star that has come to the end of its "lifetime" by running out of fuel and then gravitationally collapsing?
-white dwarf -black hole -neutron star
You push your 2 kg physics book along a tabletop, pushing it with 10 newtons of force. The frictional force on it is 4 newtons. The book's acceleration is
3 m/s2
You push your 2 kg physics book along a tabletop, pushing it with 10 newtons of force. If the book is greased so that friction is negligible, the book's acceleration is
5 m/s2.
The acceleration due to gravity is 10 m/sec2. If an object falls from rest, its instantaneous speed at the end of the fifth second is (neglecting air resistance)
50 m/sec
A rocket taking off straight upward develops a thrust of 10,000 newtons. The rocket weighs 2,000 newtons. The net force on the rocket, neglecting air resistance, is
8,000 newtons
Mary pushes horizontally on a large, heavy table which is standing alone in the middle of a room, and notes that the table does not move despite the fact that she is pushing on it (see the figure). Why doesn't the table move?
A frictional force is also exerted by the floor on the table, and this force is equal and opposite to the pushing force
You would be richest if your hunk of gold had a mass of one kilogram
Actually it wouldn't make any difference
Evidence that things are made of atoms comes from
Brownian motion
An automobile travels at an unchanging speed of 80 km/hr on a straight level road. Which of the following best represents the overall energy process occurring here?
Chem E =>Thermal E
How does a permanent magnet work, i.e., what is the explanation of its magnetic effects?
Electrons orbiting individual atoms in the magnet are all aligned together so that their orbital motion produces a large overall effect.
According to current theories, how did the sun's planets get here?
Part of the gas and dust that gathered together to form the sun went into orbit around the sun instead of falling into the sun, and this part formed the planets.
Under what condition can a force act on an object and yet do no work on that object?
If the object does not move.
In the figure, the moon is moving clockwise in a circular orbit around Earth. Imagine that gravity was suddenly shut off, throughout the solar system, at the instant when the moon is in the position shown in the figure. How would the moon move, after gravity was shut off?
In the direction of arrow B, in a straight line
What is one "kilowatt-hour" [kW · h]?
It is the energy output of one kilowatt operating for one hour.
In order for you to get out of bed with the least amount of work, would it be better for your bed to be on the floor or a meter high?
It would be better for the bed to be a meter high, because then you would not need to do as much work in lifting yourself to your feet.
What form(s) of energy does the falling rubber ball have when it is halfway down (see figure)?
Kinetic and gravitational
Which statement is the most accurate for falling objects on Earth?
Neglecting the effects of air resistance, all objects fall at roughly the same speed
The law of gravity was invented by
Newton
What is the present scientific status of Newtonian physics?
Newtonian physics does not apply to very small objects, high-speed objects, and very strong gravitational forces.
Are electric fields made of material particles such as atoms, and how do we know?
No, because electromagnetic waves are able to cross regions of empty space containing no material particles.
Is it possible to prove, for certain, that a scientific theory is true?
No, because it is always possible that a future experiment will disagree with the theory
Object A has twice as much mass as object B. If you exert the same force on these two objects, how do their accelerations compare?
Object A has half as much acceleration as object B
How is the gravitational force between two objects affected by changes in the masses of the objects and by changes in the distance between the two objects?
The force increases with increased mass, and decreases with increased distance.
One force acting on your body right now is your weight. Which of the following is the best description of the other member of the "force pair" [of which your weight is one member]?
The gravitational force by your body pulling upward on Earth
Which scientific theory or theories of the atom agrees with all of the atomic experiments performed to date?
The quantum theory of the atom.
A long-wavelength wave and a short-wavelength wave both move along the same rope. Which wave has the higher frequency, and which wave carries more energy, assuming their amplitudes are the same?
The short-wavelength wave has the higher frequency and carries more energy.
Suppose you released a single proton from rest at some point X in an electric field, and that you then released a single electron from rest at the same point X. How would the motions of the proton and electron compare, just after their release from rest?
They would move in opposite directions, and the electron would move fastest.
Two water waves, call them X and Y, have the same amplitude, but X has a higher frequency than Y. Regarding their wavelengths and their energies,
Y has the larger wavelength and X carries the greater energy.
Do physicists consider electromagnetic fields to be "real"?
Yes, because electromagnetic fields contain energy, even though they are not made atoms.
Is it possible for an object to accelerate but without changing its speed?
Yes, for example when a car turns a corner while maintaining an unchanging speed
Is any force exerted on you when you slow down while moving along a straight line?
Yes, there is a backward force on you, opposite to your direction of motion
Is it possible to send waves to the moon from Earth?
Yes, we could send an electromagnetic wave.
In Copernicus's theory, retrograde planetary motion is explained as
a result of Earth's motion: as Earth passes another planet, that planet appears to move backward as seen against the background stars
Suppose an automobile's fuel could be made to burn hotter without harming the engine's operation. Would you still get the same amount of useful work from each gallon of gasoline?
You would get more work, because heat engines are more efficient at converting thermal energy into work when the input temperature is higher.
Which of these is not accelerating?
a car while it is moving at unchanging speed up a straight [or steady] incline
While a rock is falling straight down it has
a constant [or unchanging] acceleration
Two brief waves or "pulses" are sent down a rope, in opposite directions, as shown in the figure. Pulse A is 1 cm in height, and pulse B is 2 cm in depth. When they meet, they will create
a disturbance 1 cm deep.
If two electrons are at rest a short distance apart, they will feel
a repulsive electric force, but no magnetic force.
At the microscopic level, electric currents in wires are due to
electrons traveling along the wire.
Which of the following is transported by all traveling waves?
energy
A gas can containing a gallon of gasoline is stored in a basement. This gasoline contains
energy.
To what two quantities is work proportional?
force and distance
Different colors correspond to electromagnetic waves of different
frequencies.
Which part of the electromagnetic spectrum has the shortest wavelength?
gamma
The energy transformation that occurs during downhill skiing is
grav E => kin E + therm E
The law of inertia says that
if there is no force on a body, the body will have no acceleration
Imagine that you could magically move the moon closer to Earth, so that the distance from Earth to moon is cut in half. This would cause the force that Earth exerts on the moon to be
increased to four times its original value
Which of the following does not travel at light speed?
infrared waves, light, x-rays, and radio waves all travel at light speed
A defining feature of "pseudoscience" is
it does not use proper scientific methodology
Earth's "greenhouse effect" problem is important because
it might warm up our entire planet.
Two electromagnetic have different frequencies but equal amplitudes. The one with higher frequency has the
shorter wavelength
A book is given a brief shove along a table top and released so that it slides a short distance and comes to rest. Galileo would say that the book stopped because
of friction
You would be richest if your hunk of gold weighed 10 newtons
on the moon.
A certain grapefruit on Earth has a mass of one kilogram and a weight of one newton. When the grapefruit is on the moon its mass is
one kilogram
Regarding the relation between acceleration, force, and mass, an object's acceleration is
proportional to the force on it and inversely proportional to the object's mass
Which part of the electromagnetic spectrum has the lowest frequency?
radio
The figure above shows a marble rolling freely back and forth along a curved track. The track is positioned vertically. Assuming no friction and no air resistance, the total energy of the marble
remains the same when the marble rolls from A to B
NASA satellites stay up because
they are moving so fast that they are able to "fall" around Earth
The very earliest Greek theory of the structure of the universe pictured Earth at the center with the planets revolving around it at an unchanging rate in simple circles. The Greeks later revised this theory because
they observed that the planetary motions are irregular and include such things as retrograde motion
A primary reason for you to learn science, according to the textbook's opening section, is
to increase your awareness.
Small ripples on the surface of a pond are
transverse waves in a two-dimensional medium.
Light waves are
traveling disturbances in an electromagnetic field
Two different continuous water waves on the surface of a pond would be expected to have roughly the same
wave speeds.
The force needed to maintain a body at constant speed in outer space [far from all outside influences] is equal to
zero
You hold a 2 newton apple, having a mass of 0.2 kg, at rest in your hand. The net force on the apple is then
zero
