final Flashcards
Which has zero acceleration? A)an object at rest B)an object moving at constant velocity C)an object in equilibrium D)all of the above E)none of the above
D) All of the above. Acceleration is a change in speed and/or velocity.
A car traveling at 100 km/h strikes an unfortunate bug that splatters on the windshield. The force of impact is greater on the
A) car.
B) bug.
C) same for both
C) The same for both.
Newton’s Third Law. Every action has an equal and opposite reaction. Forces are equal and opposite.
The unit for weight is
A) Newton, N
B) kilogram, kg
A) Newton, N
Which one of the following is not in equilibrium?
A) a car on cruise control heading South
B) the Moon orbiting the Earth .
C) all of these
D) a book at rest on a table
B) The moon orbiting the earth. Orbiting = constant change in direction. Equilibrium = no change in direction or speed.
A kilogram (kg) is a measure of an object's A) force. B) weight. C) gravity. D) mass.
D) Mass.
When a baseball player hits a ball with a force of 1000 N, the ball exerts force on the bat of
A) 1000 N.
B) less than 1000 N.
C) more than 1000 N.
A) 1000 N.
Newton’s Third Law. Every action has an equal and opposite reaction. Forces are equal and opposite.
A moving object has A) energy. B) velocity. C) speed. D) all of the above
D) All of the above. (Energy = Kinetic Energy)
A box sliding across the floor eventually comes to a stop. Aristotle would explain this by saying
A)The box is reaching its natural state of motion - to be at rest.
B)The box has a net force on it.
C)The box’s inertia makes it stop.
D)The box encounters friction.
A)The box is reaching its natural state of motion - to be at rest
Although this is not true, this was Aristotle’s theory
An object that has twice as much mass as another object also has twice as much A)inertia. B)force. C)acceleration. D)velocity. E)all of the above
A)inertia. Inertia = an object’s tendency to resist a change in motion. If an object is twice as large, it takes twice the force to push, stop, or steer. If it’s half as large, it takes half the force to push, stop, or steer.
A 10-kg block is simultaneously pushed to the right with 20 N and to the left with 15 N. The net force on the block is A) 5 N to the left. B) 35 N to the right. C) 35 N to the left. D) 5 N to the right.
D) 5 N to the right. Think of one side as - and the other as +. The mass of the object doesn’t affect net force in this type of situation (No friction).
A 10-kg block is pushed across a friction-free horizontal surface with a horizontal force of 20 N. The acceleration of the block is A)2 m/s2. B)1 m/s2. C)5 m/s2. D)10 m/s2. E)none of the above
A) 2m/s^2.
Net Force/Mass = Acceleration
*m/s^2 = meters per second, squared
Compared with the mass of a certain object on Earth, the mass of the same object on the Moon is
A) more.
B) the same.
C) less.
B) the same.
Mass is always the same. Weight is relative to the force of gravity
While a car travels around a circular track at constant speed, its A) velocity is zero. B) both C) acceleration is zero. D) none of the above
D) None of the above. The car is turning, so it is accelerating. The car is moving, which means it has a speed and direction, so it has velocity (even though it’s not a constant velocity).
According to Galileo, the test of scientific truth is A) finding patterns in nature. B) experiment. C) logic. D) philosophical discussion.
B) Experiment
Which one of the following is not part of the Newton’s Third Law?
A) Two objects are required for a force interaction.
B) Accelerations are equal and opposite.
C) There are always two forces.
D) Forces are equal and opposite.
B) Accelerations are equal and opposite.
Newton’s Third Law discusses forces, not accelerations
Acceleration is _______________ proportional to mass.
A) directly
B) inversely
B) Inversely.
More Mass = More Inertia = Harder to change movement (speed or direction)
Acceleration = Change in movement (speed or direction)
As a ball falls, the action force is the pull of Earth on the ball. The reaction force is the
A)acceleration of the ball.
B)nonexistent.
C)air resistance acting against the ball.
D)pull of the ball on Earth.
E)none of the above
D)pull of the ball on Earth.
Newton’s Third Law. Every action has an equal and opposite reaction. Forces are equal and opposite.
Your weight is A) another word for your mass. B) the gravitational force by the Earth. C) a property of mechanical equilibrium. D) the same in all locations.
B) The gravitational force by the earth.
Weight is relative to gravitational force. You would weigh less on the moon than the earth, even though your mass is the same.
19) Inertia resists A) all of these B) acceleration C) turning D) changes in motion
A) All of these.
Acceleration is changing motion, which includes turning, speeding up, slowing down, or stopping.
Exert 100 J in 50 s and your power output is A)more than 4 W. B)2 W. C)1/2 W. D)1/4 W. E)4 W.
B) 2W
Power = Work / Time
Watts = Joules/Sec
A given net force propels an object along a straight-line path. If the mass were doubled, its acceleration would A)be half. B)double. C)quadruple. D)stay the same. E)none of the above
A) Be half.
Twice the mass means twice the force required to propel the object.
The force required to maintain an object at a constant velocity in free space is equal to A) the force required to stop it. B) zero. C) the mass of the object. D) the weight of the object.
B) Zero
Newton’s First Law. An object in constant velocity (equilibrium) without interference will stay in constant velocity (equilibrium)
23) Which one of the following has a zero net force?
A) a car doing donuts with constant speed
B) a book at rest on a table
C) the Moon orbiting the Earth .
D) a bird flying with constant speed .
B) a book at rest on a table
The net force of gravity and the table cancel out to 0.
A block is dragged at constant velocity across a level surface by a force of 6 N. What is the force of friction between the block and the surface? A) more than 6 N B) less than 6 N C) 6 N D) not enough information
C) 6N
To be at constant velocity, the net force must equal 0. Therefore the friction force and the pushing force must cancel eachother out.
25) A music console is pushed a distance of 2 m with a force of 20 N. The work done on the console is A) 40 J. B) 20 J. C) 10 J. D) 80 J. E) 2 J.
A) 40 J
Work = Force x Distance (Joules = Newtons x Meters)
Which one of the following objects is not in equilibrium?
A)The Earth orbiting the Sun
B)A car rounding a curve at a constant speed of 20 mph
C)A book falling down due to gravity alone
D)all of the above.
D) All of the above
All of these objects are accelerating, either through turning or speeding up.
If you do work on an object in half the time, your power output is
A) the same.
B) half.
C) twice.
C) Twice
Power = rate of work or work/time
A particle is being accelerated through space by a 10-N force. Suddenly the particle encounters a head-on second force of 10 N in the opposite direction. The particle with both forces acting on it
A)is brought to a rapid halt.
B)continues at the speed it had when it encountered the second force.
C)decelerates gradually to a halt.
D)theoretically tends to accelerate toward the speed of light.
E)none of the above
B) Continues at the speed it had when it encountered the second force.
When the forces meet, they will slow the particle, but then they will cancel out and the particle will enter equilibrium
Acceleration is _______________ proportional to net force.
A) directly
B) inversely
A) Directly
More force = more acceleration
30) A motor scooter accelerates when it A) decreases speed. B) changes direction. C) gains speed. D) all of the above.
D) All of the above
Acceleration = change in motion - speeding up, slowing down, turning, stopping.
Which of the following is not possible?
A)turning and not accelerating
B)moving with constant speed and accelerating
C)moving with constant speed but not constant velocity
D)all of these
The answer key says D, All of these. This is incorrect. The answer is A) turning and not accelerating.
Moving at a constant speed and turning would satisfy both B, and C. acceleration and non-constant velocity.
An object maintains its state of motion because it has A) speed. B) weight. C) mass. D) acceleration. E) all of these
C) Mass.
Mass = Inertia = inherent property to resist changes in motion
In class, I was able to pull a table cloth from underneath a plate without moving the plate. This best demonstrates that
A)the plate accelerated.
B)the plate has inertia.
C)gravity tends to hold the plate secure.
D)there is an action-reaction pair of forces.
E)none of these
B) The plate has inertia
Intertia = tendency to resist changes in motion (stayed where it was)
Which requires more work: lifting a 50-kg sack vertically 2 m or lifting a 25-kg sack vertically 4 m?
A)lifting the 25-kg sack
B)lifting the 50-kg sack
C)Both require the same amount of work.
C)Both require the same amount of work.
Work = Force X Distance
Joules = Newtons X Meters
Whenever the net force on an object is zero, its acceleration
A) is zero.
B) may be zero.
A) Is zero.
Acceleration requires force, to bring an object out of equilibrium.
Alternating current is normally produced by a A) generator. B) battery. C) Both D) Neither
A) Generator
A battery supplies a constant current (DC, Direct Current)
An alternator uses alternating KE input, producing alternating EPE output (AC, Alternating current)
The unit of resistance is the A) Coulomb. B) Ohm. C) Volt D) Joule E) Amp
B ) Ohm
The electric charge on all electrons
A) vary from atom to atom.
B) vary from ion to ion.
C) Are identical
C) Are identical
4)The source of electrons lighting an incandescent light bulb is A)atoms in the light bulb filament. B)the source voltage. C)the electric outlet. D)the power company. E)the wire leading to the lamp.
A) Atoms in the filament
Charges (electrons) flow, atoms stay put.
An electron and a proton
A)attract or repel depending on distance.
B)repel each other.
C)attract each other.
C) Attract
Opposite charges attract, same charges repel
The current in the wires of an AC A)changes direction. B)is nonexistent. C)remains relatively constant. D)changes via the inverse square law. E)none of the above
A) Changes direction
Hence the label alternating current
Maximum magnetic force on a current-carrying wire occurs when the wire is
A)in the same direction as the magnetic field.
B)at an angle other than 90° to the magnetic field direction.
C)opposite to the magnetic field direction.
D)perpendicular to the magnetic field direction.
E)none of the above
D)perpendicular to the magnetic field direction.
Magnetic and Electric fields are perpendicular to each other
The nucleus of an atom is charged A) negatively. B) positively. C) both D) none of the above
B) Positively
The nucleus consists of protons (+) and neutrons (no charge). Therefore the only charge present is positive
A difference between an insulator and a conductor is that a conductor has more A)protons than electrons. B)faster moving molecules. C)electrons than protons. D)energy than an insulator. E)none of the above
E) None of the above. A conductor has free-moving electrons, which an insulator does not have.
When a person experiences an electric shock, the origin of the electrons comprising the shock is A)the ground. B)likely a faulty lamp. C)the person's own body. D)a power plant. E)the electric field in the air.
C) The person’s own body.
Charges flow, atoms stay put. The atoms supplying the electrons are the ones that make up the body.
The electric force between charges depends on the
A) magnitude of electric charges.
B) separation distance between electric charges.
C) both
D) none of the above
C) Both
Magnitude of charges and Distance both affect the electric force between the charges
Unlike electric charges, magnetic poles cannot be
A) observed.
B) located.
C) separated
C) separated
anything with magnetic force will always have a north and a south pole
When a steady voltage is applied to one-half as much resistance, the current A) is quadrupled. B) is doubled. C) remains the same. D) is half.
B) is doubled
Current = Power/Voltage
Amps = Watts/Volts
If you strip electrons from an atom, the atom becomes
A) negatively charged
B)Positively charged
B)Positively charged
Electrons are negative, so removing them makes the positive charge stronger
The current in a conducting wire is composed of A) electrons. B) protons. C) neutrons. D) all or any of the above
A) Electrons
Electrons flow, the rest of the atom stays put
When a current-carrying wire in a magnetic field experiences no force it is likely A) parallel to the field lines. B) upside down relative to the field. C) overly insulated. D) all of the above
A) Parallel to the field lines
Magnetic and electric fields are perpendicular. The must be perpendicular to interact
To say that electric charge is conserved is to say that electric charge
A)may occur in an infinite variety of quantities.
B)will interact with neighboring electric charges.
C)can neither be created nor destroyed.
D)is a whole-number multiple of the charge of one electron.
C) Can never be created nor destroyed
Law of conservation - energy cannot be created or destroyed, only transformed
When the distance between two charges is halved, the electric force between the charges A)doubles. B)quadruples. C)is half. D)is reduced by one-quarter. E)none of the above
A) Doubles
Magnitude of charge and Distance influence electric force between charges. force between charges is inverse to distance. Larger distance = smaller force.
Two charged particles near each other are released. As they move, the Coulomb’s Law electric force on each particle increases. Therefore, the particles have
A) not enough information
B) opposite kinds of charge.
C) the same kind of charge.
B) opposite kinds of charge
Columbs law - opposite charges attract
Attracting brings them close together, less distance = more electric force on each particle
When a magnet is moved near a loop of wire,
A)a voltage is induced in the wire.
B)current is made to flow in the loop of wire.
C)electromagnetic induction occurs.
D)all of the above
E)none of the above
D) all of the above
The number of protons in the nucleus of an electrically neutral atom is equal to the number of A) electrons that surround the nucleus. B) neutrons in the nucleus. C) both D) neither
A) electrons that surround the nucleus.
+ and - cancel to make neutral atom, must be an equal number of + and -
A pair of positively-charged plastic straws tend to
A) repel each other.
B) neutralize each other.
C) attract each other
A) Repel each other
Columbs law - opposite charges attract, like charges repel
Electric potential energy is measured in units of A)volts. B)watts. C)joules. D)amperes. E)any or all of these
C) Joules
A device that converts EPE to KE is a A)transformer. B)motor. C)magnet. D)generator. E)none of the above
B) Motor
Break a bar magnet in half and each half is
A)no longer magnetized.
B)a magnet with a single pole.
C)a magnet with a N and S pole.
C) Magnet with a N and S pole
Poles cannot be separated
Compared to the mass of a proton, the mass of the electron is
A) very much less.
B) identical.
C) greater.
A) Much less
Electrons are not counted in atomic mass, if they have no countable mass, they must be much smaller than protons, which have a mass of 1
An ampere is a unit of electric A)resistance. B)current. C)energy. D)all of the above E)none of the above
B) Current
A magnetic field exists in a current-carrying coil of wire
A)if it contains a piece of iron.
B)only if the current changes.
C)with or without a contained piece of iron.
C) With or without the iron
A magnetic field is produced by the transfer of electrons from one coil to another when current changes
A negatively-charged balloon touching a wooden wall
A)pulls positive charge on the wall surface toward it.
B)polarizes molecules in the wall.
C)pushes negative charge in the wall away from it.
D)all of the above
E)none of the above
D) All of the above
Like kinds of magnetic poles repel while unlike kinds of magnetic poles
A) attract.
B) repel also.
C) May attract or repel
A) Attract
Coloumbs law. Opposites attract, like repel.
Current is what determines the poles of a magnet - charges
When the voltage across a steady resistance is doubled, the current A) is doubled. B) is quadrupled. C) is half. D) remains the same.
A) Is doubled
Current = Voltage/resistance
Amperes = Volts/Ohms
Electrons will flow in an electric circuit when
A)there is a voltage .
B)electric devices in the circuit are not defective.
C)electric resistance is low.
D)the circuit is grounded.
A) There is voltage
When you remove electrons from a metal cup, the cup becomes
A) negatively charged.
B) positively charged.
C) ionized.
B) Positively Charged
Electric potential is measured in units of A)joules. B)amperes. C)volts. D)watts. E)any or all of these
C) Volts
EP=Volts
EPE = Joules
To say that an object is electrically polarized is to say A)it is to some degree magnetic. B)it is only partially conducting. C)its charges have been separated. D)its internal EPE is zero. E)it is electrically charged.
D) Its charges have been separated
36) The electric force between charges is strongest when the charges are
A) close together.
B) far apart.
C) either
A) Close together
To say a current is dc is to say that current in the circuit
A)is parallel to the connecting wires.
B)alternates only slowly.
C)has a single direction.
C)has a single direction.
A device that converts KE to EPE is a A)motor. B)generator. C)transformer. D)magnet. E)none of the above
B)generator.
A 100-N box and a 200-N box are hoisted the same distance. Raising the heavier box requires A)twice as much work. B)less work. C)four times as much work. D)as much work. E)more than four times as much work.
A)twice as much work.
Stretch a copper wire so that it is thinner and the resistance between its ends
A) remains unchanged.
B) decreases.
C) increases.
C) Increases
Same amount of atoms in a denser configuration - more collisions - more resistance
Charge carriers in a metal are electrons rather than protons because electrons are A)smaller. B)loosely bound. C)negative. D)all of the above E)none of the above
B) Loosely bound
Electrical resistance is greater for
A) wet skin.
B) dry skin.
C) both the same
B) Dry Skin
An electromagnet consists of a
A)bar magnet that carries an electric current.
B)coil of wire.
C)current-carrying coil with a piece of iron inside.
C) current carrying coil with a piece of iron inside
When the current in a wire is reversed, the direction of the surrounding magnetic field
A) also reverses.
B) remains steady.
C) collapses.
A) Also reverses
Magnetic poles are determined by charge, and magnetic and electric fields influence each other
45) The source of all magnetism is A) tiny bits of iron. B) aligned atoms. C) moving electric charge. D) ferromagnetic materials.
C) Moving electric charge
Moving electrons act at tiny electromagnets, creating a field that magnifies the more atoms there are moving on a certain frequency
A pair of protons in an atomic nucleus repel each other, but they are also attracted to each other. Why?
A)Actually, protons do not attract one another.
B)The pair repel each other by a strong nuclear force but attract one another by an electrical force.
C)The pair attract each other by a strong nuclear force but also repel one another by an electrical force.
C)The pair attract each other by a strong nuclear force but also repel one another by an electrical force
One of the main reasons people can walk barefoot on red-hot coals of wood without burning their feet has to do with
A)low temperature of the coals.
B)the low thermal energy of the coals.
C)poor conductivity of the coals.
C)poor conductivity of the coals
When you touch a hot penny in sunlight with your finger, thermal energy flows
A)from the penny to your finger.
B)from your finger to the penny.
C)both ways
A)from the penny to your finger.
Which contributes more to an atom’s mass: electrons or protons? Which contributes more to an atom’s size?
A)Protons contribute more to an atom’s mass while electrons contribute more to its size.
B)Protons contribute more to both the mass and size of an atom.
C)Electrons contribute more to both the mass and size of an atom.
D)Electrons contribute more to an atom’s mass while protons contribute more to its size.
A)Protons contribute more to an atom’s mass while electrons contribute more to its size.
The following statement describes which subatomic particle best?
It does not have an electrical charge.
A) an electron
B) a proton
C) a neutron
D) A and B
E) B and C
C) a neutron
How do fission power plants produce energy?
A)The heat generated in the fission process is used to produce steam to drive a turbine.
B)The electrons generated in the fission process are used to produce an electrical current.
C)The neutrons generated in the fission process are used to drive a turbine.
D)none of the above
A)The heat generated in the fission process is used to produce steam to drive a turbine.
Heat is thermal energy that flows due to
A) temperature differences.
B) molecular activity.
C) calorie imbalance.
A) temperature differences.
Which is not a phase of matter?
A) liquids
B) gases
C) vacuum
D) solids
C) vacuum
The water droplets that form on a cold soda taken out of a refrigerator are due to
A) condensation.
B) evaporation.
C) convection.
D) sublimation.
A) condensation.
Convection currents in the air near a seashore are produced by
A) unequal temperatures of land and water.
B) evaporation of water.
C) shifting winds.
D) incoming and outgoing tides.
A) unequal temperatures of land and water.
The sun produces its energy by
A) convection
B) fission
C) fusion
D) conduction
C) fusion
When a gas is changed to a liquid, the gas
A) absorbs energy.
B) releases energy.
C) neither
B) Releases energy
Down the phase chain = release
The nucleus of an electrically neutral iron atom contains 26 protons. How many electrons does this iron atom have?
A) 26
B) 24
C) 52
D) none
A) 26
We feel uncomfortably warm on a humid day because water molecules are
A)undergoing convection.
B)evaporating from our moist bodies.
C)condensing on our bodies.
C) condensing on our bodies.
The molecules in a room-temperature glass of water move around at
A)no speeds as they are not moving.
B)equal speeds.
C)a wide variety of speeds.
C) a wide variety of speeds
The following statement describes which subatomic particle best?
It is a nucleon.
A) an electron B) a proton C) a neutron D) A and B E) B and C
E) B and C
The mass number of an element is ________.
A)the sum of the isotopes
B)the number of protons
C)the sum of the electrons and the neutrons
D)the sum of the electrons and the protons
E)the sum of the protons and the neutrons
B)the number of protons
In the fusion process, mass
A) is lost
B) remains the same
C) is gained
A) Is lost
E=Mc^2
mass energy is converted
Which of the following statements is true?
A)Nuclear power plants release more radioactive waste to the environment than coal burning power plants.
B)Coal burning power plants release more radioactive waste to the environment than nuclear power plants.
C)Coal burning power plants do not release any radioactive waste to the environment.
B)Coal burning power plants release more radioactive waste to the environment than nuclear power plants.
Heat is simply another word for
A) potential energy.
B) thermal energy.
C) temperature.
D) the transfer of thermal energy.
D) the transfer of thermal energy.
Compared to a giant iceberg, a hot cup of coffee has
A) higher temperature, but less thermal energy.
B) more thermal energy and higher temperature.
C) more heat and more thermal energy.
D) none of the above
A) higher temperature, but less thermal energy.
Uranium-235 releases an average of about 2 free neutrons per fission, while plutonium-239 releases an average of about 3 free neutrons per fission. Which of these elements might you therefore expect to produce more energy in a chain reaction?
A)plutonium-239
B)uranium-235
C)Neither would produce more energy in a chain reaction.
A) plutonium-239
Since atoms are mostly empty space, why don’t objects pass through one another?
A)The nucleus of one atom repels the nucleus of another atom when it gets close.
B)The electrons of one attract the nucleus of a neighboring atom to form a barrier.
C)The electrons on the atoms repel other electrons on other atoms when they get close.
D)The nucleus of one atom attracts the nucleus of a neighboring atom to form a barrier.
C)The electrons on the atoms repel other electrons on other atoms when they get close.
When you touch a piece of ice with your finger, thermal energy flows
A)from your finger to the ice.
B)from the ice to your finger.
C)both ways
A)from your finger to the ice.
Dogs will pant
A)for no particular reason–some things just happen.
B)to help evaporation occur in its mouth and bronchial tract.
C)to bring more oxygen into its lungs.
B)to help evaporation occur in its mouth and bronchial tract.
The following statement describes which subatomic particle best?
It is located outside of the nucleus.
A) an electron
B) a proton
C) a neutron
D) A and B
E) B and C
A) an electron
A good insulator
A) slows heat transfer.
B) quickens heat transfer.
C) stops heat transfer.
A) slows heat transfer.
What does the following element description actually mean?
18/6 O
A)6 oxygen atoms with 18 neutrons
B)an oxygen atom with 6 protons and 12 neutrons
C)an oxygen atom with 6 neutrons and 12 protons
D)18 oxygen atoms with 6 neutrons each
E)none of the above
B)an oxygen atom with 6 protons and 12 neutrons
Pigs will lie in mud mainly to
A)cool themselves by evaporation.
B)cool themselves by condensation.
C)decrease thermal conductivity.
A)cool themselves by evaporation.
Metals are good heat conductors due to
A) free electrons.
B) high densities of metals.
C) stiff bonds between atoms
D) loose bonds between atoms.
A) free electrons.
Which of the following sources of radiation provides most of our yearly exposure?
A)televisions (cathode ray tubes)
B)dental and medical X-rays
C)smoke detectors
D)natural background radiation
E)living near nuclear power plants
D)natural background radiation
Which of the following statements best describes why a nucleus undergoes radioactive decay?
A)There are not enough electrons surrounding the nucleus.
B)The strong nuclear force is less than the electric force.
C)There is a net charge in the nucleus.
D)The strong nuclear force is greater than the electric force.
B)The strong nuclear force is less than the electric force.
Temperature is a meaure of
A) total kinetic energy of all atoms.
B) heat flow.
C) transfer of energy from atom to atom.
D) kinetic energy per atom.
D) kinetic energy per atom.
When a solid is changed to a liquid, the solid
A)releases energy.
B)absorbs energy.
C)neither releases nor absorbs energy.
B)absorbs energy.
Up the phase chain = absorb
Which of the following statements describes isotopes?
A)atoms with the same number of neutrons but a different number of protons
B)atoms with the same number of neutrons but a different number of electrons
C)atoms with the same number of protons but a different number of neutrons
D)atoms with the same number of protons but a different number of electrons
E)none of the above
C) atoms with the same number of protons but a different number of neutrons
