Physics Thermodynamics, Ch. 18 Homework, Physics Chapter 19 Review, Chapter 10, Physics chapter 20, Unit 4 Practice Exam
If a cup of tea at room temperature, 24°C is heated until it has twice the internal energy, unlike a piece of metal, its temperature will be
100°C
A heat engine is operating with the hot reservoir at 510 K and cold reservoir of 295 K. The engine gives off 2500 J of heat. What is the maximum amount of work the engine can produce?
1054 Joules
the amplitude of a wave is 1 meter. the crest-to-trough distance of the wave 0.5 m 2 m 1 m none of the above
2
an object that completes 20 vibrations in 10 seconds has a frequency of 0.5 hertz 2 hertz 200 hertz 1 hertz
2 hertz
a fishing boat captain returns to port saying its rough out there with waves that are 4 meters. He is probably talking about of waves of amplitude 3 m 2 m 4 m 1 m
2 m
If the efficiency of a heat engine is e = 0.2. We say that the engine is 20% efficient. How much input heat is converted to work?
20%
A gas expands from an initial volume of 0.40 m^3 to a final volume of 0.62 m^3 as the initial pressure is 110 Pa. Calculate the work done by the gas. W = P i (V f - V i)
24.2 J
When WORK is done by the system, the amount of work done can
decrease the temperature and decrease thermal energy.
Harry places a new air conditioner in the middle of his hot room, which when operating
further warms the room
if you double the frequency of a vibrating object, its period is quartered halves doubles
halves
A ___ is a device that converts thermal energy into work.
heat engine
An adiabatic process is characterized by the absence of
heat exchange.
Heat engines such as jet engines are more efficient when run at
high temperature differences.
The direction of natural processes is from states of
higher order to lower order.
To wholly convert a given amount of heat energy into mechanical energy is
impossible regardless of the technique used.
A wiggle in time is
vibration
Chinook winds tend to
warm an environment.
Processes can proceed from disorder to order
when input energy is supplied.
It is possible to cool objects to extremely low temperature but we have never reached
0 Kelvin.
the frequency of a certain wave is 10 hertz and its period is 10 seconds 0.1 second 100 seconds none of the above
0.1 second
an object that completes 10 vibrations in 20 seconds has a frequency of 200 hertz 2 hertz 0.5 hertz
0.5 hertz
A heat engine with an efficiency of 24.0% performs 1250 J of work. Find the heat absorbed from the hot reservoir.
5210 J
Adiabatic processes occur in Earth's oceans. atmosphere. mantle. all of the above none of the above
all of the above
Water freezes at atmospheric pressure and a temperature of about 273 kelvin. 0 degrees Celsius. 32 degrees Fahrenheit. all of the above none of the above
all of the above
both a transverse wave and a longitudinal wave have speed wavelength amplitude frequency all of the above
all of the above
A heat engine would have 100% efficiency if its low-temperature reservoir were
at absolute zero.
Entropy is a measure of messiness. disorder. both of the above
both of the above
When mechanical work is done on a system, an increase normally occurs in its temperature. internal energy. both of these neither of these
both of these
When you vigorously shake a can of chicken broth, you increase the temperature of the broth. are doing work on the broth. both of these
both of these
The second law of thermodynamics tells us that heat cannot flow from
cold to hot without external energy.
Your hand is warmed when you blow on it with your mouth open, but when your lips are puckered so that air expands as you blow, your hand is
colder
A heat engine will increase its efficiency if it produces
greater work output for the same heat input.
the frequency of a simple pendulum does Not depend on its acceleration due to gravity its length its mass all of the above none of the above
its mass
If a blob of air is swept upward with no heat input or output,
its temperature decreases.
As a blob of air at high elevation sinks to a lower elevation with no heat input or output,
its temperature increases.
The first law of thermodynamics is a restatement of the
law of conservation of energy.
High-quality energy in natural processes has a tendency to transform into
lower quality energy.
Systems alone tend to move toward a state of
more entropy.
During an adiabatic compression of an ideal gas
no heat enters or leaves the gas.
A given amount of heat energy can be completely converted to mechanical energy in
none of the above
The main purpose of the condenser in the steam cycle of a steam turbine is to
ower pressure on the back side of the turbine blades
To convert a given amount of mechanical energy into some heat is
possible.
To totally convert a given amount of mechanical energy into heat is
possible.
A definite method for losing weight is
reduce Calorie intake.
Entropy is most closely related to the
second law of thermodynamics.
if a child swinging to and fro on a playground swing stand up, her time for a to and fro swing is shorter unchanged longer
shorter
the pendulum with the greatest frequency is one with the longest length shortest length neither of these
shortest length
a pendulum clock at high altitudes runs normally as it does at sea level slow fast
slow
the source of all waves is energy something that vibrates a force of some kind all of the bove none of the above
something that vibrates
Thermal energy of a system is the
sum of all its kinetic and potential energy.
Suppose the temperature of the hot reservoir in a heat engine does not change. As the cold reservoir temperature is lowered,
the efficiency of the engine increases.
Your locker gets messier each week. In this case,
the entropy of your locker is increasing.
The greater the difference in temperature between the hot reservoir and cold reservoir for a heat engine,
the greater the efficiency.
The greater the difference in temperature between the input reservoir and output reservoir for a heat engine,
the greater the efficiency.
When work is done on a system, for example, compressing air in a tire pump,
the temperature of the system increases.
Internal energy in thermodynamics is the same as
thermal energy.
A wiggle in both space and time is a
wave
Blow on your hand with your open mouth and you feel the warmth of your breath. Pucker your lips and blow so that adiabatic expansion occurs and
your breath is cooler.
a 60 vibration per second wave travels 30 seconds in 1 second. its frequence is 60 hertz and it travels at 30m/s 1800 hertz and it travels at 2 m/s 30 hertz and it travels at 60 m/s none of the above
60 hertz and it travels at 30 m/s
If the efficiency of a heat engine is e = 0.2. We say that the engine is 20% efficient. How much waste heat is exhausted into the air?
80%
The ideal efficiency for a heat engine operating between the temperatures 2700 K and 300 K is
89%.
Entropy is closely related to the
Second Law of Thermodynamics.
Earth's atmosphere gets most of its heat from the
Sun.
The contained air in a closed, sealed can placed on a hot stove will undergo an increase in
Temperature, Internal Energy, and Pressure
During an isothermal process 350 J of heat is added to a gas. Which is true?
The gas does 350 J of work.
___ is an object, like a large body of water, that supplies or receives thermal energy with essentially no change in temperature.
Thermal reservoir
The __ states It is impossible to lower the temperature of an object all the way to absolute zero.
Third Law of Thermodynamics
Two identical blocks of iron, one at 10ºC and the other at 20ºC, are put in contact. Suppose the cooler block cools to 5ºC and the warmer block warms to 25ºC.
This would violate the Second Law of Thermodynamics.
Every heat engine You Answered converts energy into mechanical work. expels heat to a lower-temperature reservoir. gains heat from a high-temperature reservoir. all of the above none of the above
all of the above
In the formation of a cloud, moist air rises and condenses. expands. cools. all of the above none of the above
all of the above
the stride of a horse would be quicker if more mass in its legs were concentrated halfway up its leg towards its feet n the upper part, nearer the horse's body uniformly all along its legs none of the above
in the upper part, nearer the horse's body
If you leave the refrigerator door open in a closed room, the room temperature will
increase
When HEAT is added to a system, the amount of heat added can
increase the temperature and increase thermal energy.
When an ideal gas is subjected to an adiabatic process the internal energy of the gas does not change. no work is done on the gas. the temperature of the gas does not change. all of the above none of the above
none of the above
Which of these is affected by mass? an object sliding down a friction free plane a pendulum a freely-falling object all of the above none of the above
none of the above
an object that completes 100 vibrations in 5 seconds has a period of 1 second 2 seconds 0.5 second none of the above
none of the above
The amount of energy ultimately converted to heat by an incandescent light bulb is about
100%
An equal amount of 0°C air that is twice as hot has a temperature of
273°C.
If a 5°C piece of iron is heated until it has twice as much internal energy, its temperature will be
283°C.
If a 10°C piece of iron is heated until it has twice as much internal energy, its temperature will be
293°C.
The change in internal energy of adding 100 joules to a system that does 60 joules of work is
40 J.
The ideal efficiency for a heat engine operating between the temperatures of 227°C and 27°C is
40%
Systems that are left alone, tend to move toward
a state of more entropy.
A soda-pop can containing only steam is placed top downward in a pan of water. Whap! The can is dramatically crushed by atmospheric pressure. The reduced pressure inside the can is due to
condensation of steam inside.
A process that occurs while the pressure remains constant is referred to as a
constant-pressure process.
A process that occurs while the volume of a system remains constant is referred to as a
constant-volume process
As a parcel of air is swept upward, with no heat input or output, its temperature
decreases.
Entropy measures
disorder.
Systems alone tend to move toward
disorder.
The ___ of a heat engine is the fraction of heat supplied to the engine that is converted to work.
efficiency
As entropy in a system increases,
energy in the system becomes less ordered.
The first law of thermodynamics is a restatement of the conservation of
energy.
As a system becomes more disordered,
entropy increases.
when an elevator is accelerating upward, the frequency of a pendulum inside doesn't change increases decreases
increases
As a parcel of air at high altitude sinks to a lower elevation with no heat input or output, its temperature
increases.
As a system becomes more disordered, entropy
increases.
When you compress air with a tire pump, the air temperature in the tire
increases.
Which best describes a process in which the work done equals the heat?
isothermal
