Physics Final
Calculate the acceleration of a 1800-kgkg, single-engine airplane as it begins its takeoff with an engine thrust of 700 NN. (FYI: The unit N/kgN/kg is equivalent to m/s2m/s2.)
0.39 (700/1800)
In a circuit of two lamps in series, if the current through one lamp is 1 AA, what is the current through the other lamp?
1 A The same current flows through lamps in series.
What is the volume of a sugar cube that measures 1 cm on each side? What is the cross-sectional area of the cube? The total surface area?
1 cm3, 1 cm2, 6 cm2
Two objects were initially neutral. After they were rubbed against each other, it is determined that one of them has n electrons in excess. What can you say about the charge of the second object? (There may be more than one right answer.)
1.) It has an excess positive charge. 2.) It is missing n electrons.
What is the frequency of vibration of the electron in the antenna of a station broadcasting at 101.7 MHz on the FM dial?
101.7 million vibrations per second
Determine the useful energy output of a simple machine with 90 percent efficiency if the total energy input is 200 Joules?
180 Joules
A medium size apple weighs 1 NN and sits on an area of about 4 cm2cm2 (0.0004 m2m2). Determine the pressure that the apple exerts on the surface.
2,500 Pa
If a voltage of 6 VV is impressed across the circuit of two lamps in series and the voltage across the first lamp is 2 VV, what is the voltage across the second lamp?
4 volts. The sum of the voltages across each lamp must add up to the total voltage across both lamps.
A 7-N vector at an angle of 45° to the horizontal has a vertical component that is about _______.
5 N
In its first second of free fall, a dropped softball will fall a vertical distance of ______.
5 m
How much energy is given to each coulomb of charge that flows through a 6-VV battery?
6 joules
In a circuit of two lamps in parallel, where there is a voltage of 6 V across one lamp, what is the voltage across the other lamp?
6 volts
A toaster has a heating element of 19 ΩΩ and is connected to a 120-VV outlet.
6.3 (120/19)
Calculate the power of a hair dryer that operates on 90 VV and draws a current of 9.0 AA.
810 (9.0 x90)
An electric toy draws 0.75 AA from a 120-VV outlet.
90W (0.75x120=90w)
A popular saying is "The bigger they are, the harder they fall." Does this relate more to a small or a large ratio (surface area)/(volume)?
A big creature has a small ratio of surface area to volume, so air resistance doesn't slow it as much when it falls.
What is induced by a changing magnetic field?
A changing electric field
An electric field is induced by ______________.
A changing magnetic field
What is induced by a changing electric field?
A changing magnetic field
Does a substance that heats up quickly have a high or a low specific heat capacity?
A low specific heat capacity
Why can small creatures fall considerable distances without injury, while humans need parachutes to do the same?
A small creature has greater surface area per unit mass, so air resistance slows it more when it falls.
Rank the voltage readings from greatest to least.
A,B,C
A.) Two identical cars are driving in opposite directions at the same speed. Their kinetic energies have ____. B.)A motorcycle drives up a steeply inclined ramp. The work done on the motorcycle by the Earth's gravitational force is ____. C.)During a certain time interval, the net work done on an object is zero joules. We can be certain that ____.
A.) the same magnitude and sign B.) Negative C.) the object's final speed was the same as its initial speed
What is the distinction in this book between passively and actively observing an event?
Active observing requires interacting with the system being observed, whereas passive observing does not.
In terms of net charge, how does an electrically polarized object differ from an electrically charged object?
An electrically polarized object can have zero net charge, while a charged object cannot have zero net charge.
When you bat a ball, does the ball react at the same time, or a bit later?
At the same time.
An old man and his grandchild, both of the same mass, go up the stairs to their first-floor apartment. The child gets to the apartment well before his grandad. Which one gained more potential energy?
Both gained the same potential energy
Rank the current readings in the ammeter, from greatest to least.
C,B,A
What is meant by a temperature inversion?
Condition wherein upper regions of atmosphere are warmer than lower regions.
Distinguish between constructive interference and destructive interference.
Constructive interference occurs when the crests of two waves add together. Destructive interference occurs when a crest of one wave is reduced by the trough of another.
At what speed do electrons in a battery driven automotive circuit travel along a wire? At what speed does the electric field propagate along a wire?
Electrons move at 0.01 cm/s. The electric field propagates at nearly the speed of light.
When you make your monthly household electric payment, which of the following are you billed for: voltage, current, power, energy?
Energy
What would happen if light was moving at a lower speed?
Energy would be lost and none would be transported from one place to another.
Knowing that k𝑘 is 9.0×109N⋅m2/C29.0×109N⋅m2/C2 (the proportionality constant for Coulomb's law), select the correct equations that show that the force between the charges is 9.0×109N9.0×109N.
F=kq1q2r2=(9.0×109N⋅m2/C2)⋅(0.4C)⋅(0.4C)(0.4m)2=9.0×109N
Given that k=9.0×109N⋅m2/C2𝑘=9.0×109N⋅m2/C2 (the proportionality constant for Coulomb's law), select the correct equations that show that the force between the charges is 2.25×1011N2.25×1011N.
F=kq1q2r2=(9.0×109N⋅m2/C2)⋅(0.5C)⋅(0.5C)(0.1m)2=2.25×1011N
Does sound travel faster in warm air or in cold air? In humid air or dry air?
Faster in warm air, faster in humid air
What keeps the atmosphere around our planet?
Gravity
Cite two examples of common force fields.
Gravity fields made by mass, electric fields made by charge
What is the role of temperature with regard to the direction of internal energy flow?
Heat flows spontaneously from high temperature to low temperature.
How does the constant speed c𝑐 of an electromagnetic wave in free space relate to the conservation of energy?
If light slowed down (sped up), its energy would decrease (increase), thereby violating the law of conservation of energy.
What is a node? What is an antinode?
In a standing wave, a node always has zero displacement and an antinode always has maximum displacement.
What is an electric dipole?
In an electric dipole, positive and negative charges are separated on opposite sides of an object.
What is meant by saying that a certain current is 60 HzHz?
It alternates back and forth 60 times a second.
What is the distance fallen for a ball in free fall 1 ss after being dropped from a rest position? What is the distance for a 5-ss drop?
It falls 5 mm in 1 ss and 125 mm in 5 s
What is the gain in speed per second for a freely falling object?
It gains approximately 10 m/s.
If the voltage impressed across a circuit is held constant while the resistance doubles, what change occurs in the current?
It is cut in half.
The temperature scale favored by scientists is ___________.
Kelvin
When does light behave as a wave? When does it behave as a particle?
Light is emitted and detected as a particle and travels as a wave.
Why do photographs in a book or magazine look grainy when magnified?
Magazine photographs are composed of individual dark spots resulting from photons of light interacting with electrons in grains of silver in film or in digital detectors.
Distinguish between mass number and atomic mass.
Mass number is the number of nucleons; atomic mass is the total mass of an atom.
Which of Newton's three laws focuses on interactions?
Newton's third law
Does the medium in which a wave travels move with the wave?
No
How many forces act on an object in free fall?
One force, the force due to gravity.
How does the second law of thermodynamics relate to heat engines?
Only part of the input heat can be converted to work in any engine.
Calculate the water pressure at the bottom of a 50-mm-high water tower.
P = 1000 × 9.80 × 50 P = 490000 N / m 2 .
When electrons are diffracted through a double slit, do they hit the screen in a wavelike way or in a particle-like way? Is the pattern of hits wavelike or particle-like?
Particle-like, wavelike
What evidence supports the wave nature of particles?
Particles exhibit two-slit interference.
Compare the pressure against the floor standing on one foot versus standing on both feet.
Pressure is twice as much on the floor when you stand on one foot.
How do speed and velocity differ?
Speed is how fast, a scalar quantity. Velocity as a vector quantity states how fast and which direction.
Why does sound tend to bend as it grazes warm ground?
Speed of sound increases in the warmed air, so sound refracts upward.
If the net force acting on a sliding block is somehow doubled, what happens to the acceleration?
The acceleration is reduced to half of its original value.
If the mass of a sliding block is somehow doubled at the same time the net force on it is doubled, how does the resulting acceleration compare with the original acceleration?
The acceleration remains the same.
An old man and his grandchild, both of the same mass, go up the stairs to their first-floor apartment. The child gets to the apartment well before his grandad. Which one delivered more power?
The child
Does the strength of a person's arm depend more on its length or its cross-sectional area?
The cross-sectional area
What part of a rectangle formed by velocity vectors represents the resultant speed?
The diagonal of the rectangle.
Where is the energy stored in a capacitor?
The energy is stored in the electric field between the plates.
If two objects of the same size move through the air at different speeds, which encounters the greater air resistance?
The faster object encounters more air resistance.
How does magnetic field strength relate to the closeness of magnetic field lines about a bar magnet?
The field strength is stronger where the field lines are closer.
Why does a long cannon impart more speed to a cannonball than a small cannon for the same force?
The force is applied for a longer time in the long cannon.
Compared to hydrogen (atomic number 1), the helium atom (atomic number 2) has double the positive charge in the nucleus. How do you compare their relative sizes?
The helium atom is smaller than the hydrogen atom.
A fresh breeze is felt on the shore with the sunset, because ground cools faster than the ocean. Which one has a higher specific heat?
The ocean
A lab technician has six identical lamps and two identical power sources and uses them to build two circuits, one in series and one in parallel. What can be stated about the electrical resistance for each circuit?
The parallel circuit will have a lower resistance.
If two identical sacks are lifted the same vertical distance in the same time, how does the power required for each compare?
The power is the same.
The narrower pipes in your home are those feeding your faucets and showers. Compared to the water pressure in the large pipes running to your home, what would the internal pressure of the water flowing through the small pipes be?
The pressure in the small pipes would be the lowest because water moves there at the highest speed.
The ratio circumference/diameter for all circles is π𝜋. What is the ratio force/mass for freely falling bodies?
The ratio is g.
Identify the force that propels a rocket.
The rocket is propelled by the reaction force from the particles accelerated out the rear by an action force from the rocket.
Which has a greater momentum, a heavy truck at rest or a mouse running along the street?
The running mouse.
Compared with the energy it takes to separate oxygen and hydrogen from water, how much energy is released when they recombine? (Think conservation of energy.)
The same amount of energy is released when they recombine.
What is the result of a mirror image of a sound signal combining with the sound itself?
The sound is cancelled when added to its mirror image.
Why will a dropped metal spoon vibrate when hitting a floor, whereas a dropped napkin won't?
The spoon tends to retain its shape, while the napkin does not
What relationship did Galileo discover between a ball's acceleration and the steepness of an incline?
The steeper the incline, the greater the acceleration.
How do the vertical and horizontal components of velocity change for a ball tossed at an upward angle?
The vertical component decreases in magnitude until it reaches the maximum height and then increases; the horizontal component is constant.
A sound wave is refracted when it moves from air to water, what happens to the speed of the wave front?
The wave fronts travel at different speeds in air and in the water.
What relative direction between a magnetic field and a current-carrying wire results in the greatest force?
The wire should be perpendicular to the field.
A car accelerates from 10 m/s to 30 m/s in 4 seconds, and then slows down to 20 m/s in 2 seconds. What can you say about the net force acting on the car for both intervals?
They are equal and opposite.
True or false: Kinetic energy is the energy something has by virtue of motion.
True
True or false: Gravitational potential energy is the energy something has relative to some reference level.
True.
What is the relationship among frequency, wavelength, and wave speed?
Wave speed is frequency multiplied by wavelength.
Does light travel from one place to another in a wavelike or a particle-like way?
Wavelike
How do forced vibrations relate to resonance?
When forced vibrations match an object's natural frequency, resonant amplification occurs.
When is a capacitor fully charged?
When voltage between the plates and the potential difference between the battery terminals have equalized.
What is the error in saying the source of electrons in a circuit is the battery or generator?
Wires are full of mobile electrons.
Is it correct to say that, if no net impulse is exerted on a system, then no change in the momentum of the system will occur?
Yes, always.
Is it correct to say that an electric motor extends the physics that underlies a galvanometer? Why?
Yes. The deflection forces are the same, but the direction of current in the motor is reversed cyclically.
If a certain material heats up quickly and cools down quickly, the material has ___________.
a low specific heat
Magnetic domains are composed of clustered _________.
aligned iron atoms
When a parcel of air sinks in the atmosphere, there is usually _________.
an increase in temperature
A wave is a periodic vibration in ______________.
both space and time
The magnetic field about a straight length of current-carrying wire is _________.
circular in shape
The second law of thermodynamics tells us that heat does not flow from _________.
cold to hot without external energy
When the filament breaks in one lamp in a parallel circuit, lamps in other branches of the circuit normally _________.
continue glowing, but slightly brighter
When air rapidly expands, its temperature normally _________.
decreases
In one word, what is it that moves from source to receiver in wave motion?
disturbance
Electromagnetic waves are composed of _________.
electric and magnetic fields
The relation f ~ T tells us that high temperature sources emit electromagnetic waves of _________.
high frequency
A 4-mm-tall barrel is filled with water (with a weight density of 10,000 N/m3N/m3).
idk
A droplet of ink in an industrial ink-jet printer carries a charge of 1.9×10−10C1.9×10−10C and is deflected onto paper by a force of 3.5×10−4N3.5×10−4N.
idk
An electric iron connected to a 110-VV source draws 8.6 AA of current.
idk
An energy of 0.11 JJ is stored atop the metal sphere of a Van de Graaff generator. A spark carrying 1.0 microcoulomb (10-6 CC) discharges the sphere.
idk
On a chilly 6.0 ∘C∘C day, your friend who loves cold weather says she wishes it were twice as cold.
idk
What impulse occurs when the same force of 9.0 NN acts on the cart for 2.8 ss twice?
idk
What is the pressure at the bottom of the barrel when water is added to fill the pipe to its top? (This activity sometimes bursts a barrel!)
idk
Write this relationship in terms of traveling a distance of 1 wavelength in a time of 1 period. Express period as 1/frequency.
idk
Do adiabatic parcels occur in the atmosphere, in the ocean, or in both?
in both of the above (ocean & Atmosphere)
The phenomenon of beats is most closely related to _________.
interference
Air resistance on a parachutist at terminal speed _______.
is greater for a heavier person
The electromagnetic waves having the highest speed in free space are _________.
none in particular as gamma, radio, and light have the same speed
How many forces act on a freely falling object?
one
When an iron rod is placed inside a current-carrying coil of wire _________.
the coil becomes a stronger electromagnet
A ball rolling down an inclined plane each second picks up ______.
the same amount of speed each second
When a cue ball strikes an 8 ball head-on in a game of pool, the cue ball _______.
transfers its momentum to the 8 ball
The electromagnetic radiation mostly absorbed in ordinary glass is _________.
ultraviolet
The photoelectric effect is best stimulated by _________.
ultraviolet light
Determine the increase in the nail's temperature. (Assume that the specific heat capacity of steel is 420 J/kg⋅∘CJ/kg⋅∘C).
unkown
The magnetic force that acts on an electric charge at rest is _________.
zero
The net charge on an energized capacitor is normally _________.
zero
