chapter 3

In a well-insulated room, a 500 W electric heater is used to provide space heating to the air in the room. If the control volume of the system includes the electric heater only, determine respective changes of total energy, work, and heat transfer.

0 W, 500 W, -500 W

A potato is baked in an oven. Considering that any moisture loss from the potato is disregarded and the oven is well insulated, if 2 kJ of heat is transferred to the potato, what is the energy change of the potato?

2kJ

The torque applied to the shaft of a car is 180 N··m and the shaft rotates at a rate of 3000 rpm. What is the power transmitted through the shaft?

56.52 kW

Energy transfer is involved in each of the following systems. Select the ones that involves mainly work interaction. (Check all that apply.) Multiple select question. A rising piston A rotating shaft A gas turbine Boiling water on a gas stove Water heated in a tub

A rising piston A rotating shaft A gas turbine

Which of the following is NOT true regarding heat transfer? Multiple choice question. Heat requires a temperature difference. Heat is a form of energy transfer. A system at a high temperature possesses more heat than a system at a lower temperature. Heat occurs between two systems or a system and its surroundings.

A system at a high temperature possesses more heat than a system at a lower temperature.

Which of the following statements are true regarding the similarities between heat and work? (Check all that apply.) Multiple select question. Both heat and work can cross the boundary of a system. Both heat and work are associated with a thermodynamic state. Both heat and work are path functions. Both heat and work are associated with a process. Systems possess energy, including heat and work.

Both heat and work are path functions. Both heat and work can cross the boundary of a system. Both heat and work are associated with a process.

Select the statements below that best express the first law of thermodynamics. (Check all that apply.) Multiple select question. If two bodies are in thermal equilibrium with a third body, they are in thermal equilibrium with each other. Energy can neither be created nor destroyed. Energy is conserved. Heat flows in the direction of decreasing temperature. Energy has quality as well as quantity. The change in the total energy for a closed system during an adiabatic process must be equal to the net work input.

Energy can neither be created nor destroyed. Energy is conserved. The change in the total energy for a closed system during an adiabatic process must be equal to the net work input.

Select all of the statements below that use heat in the thermodynamic sense. (Check all that apply.) Multiple select question. The steam vapor has more heat than liquid water. Fire is used to heat a pot of water. A hot cup of coffee contains a lot of heat. Heat is transferred from a warmer body to a cooler one.

Fire is used to heat a pot of water. Heat is transferred from a warmer body to a cooler one.

Which ones of the following are examples of mechanical work? (Check all that apply.) Multiple select question. Magnetic work Spring work Shaft work Electrical work

Spring work Shaft work

Select all of the ways in which a process can be adiabatic. (Check all that apply.) Multiple select question. No work crosses the system boundary. The system does not change temperature during the process. The system is at the same temperature as the surroundings. The system is well insulated.

The system is at the same temperature as the surroundings. The system is well insulated.

There are two requirements for a boundary work interaction between a system and its surroundings to exist. Please select the two correct answers from the following: (Check all that apply.)

There must be a force acting on the boundary The boundary must move.

Following the formal sign convention, which of the following heat and work interactions indicate a positive sign convention for a system? (Check all that apply.) Multiple select question. Work done to the system Heat transfer out of the system Work done by the system Heat transfer to the system

Work done by the system Heat transfer to the system

For a simple compressible system, the change in the total energy of the system during a process is the sum of the ______. Multiple choice question. changes in its potential and internal energies changes in its potential, kinetic, and internal energies changes in its potential and kinetic energies changes in its kinetic and internal energies

changes in its potential, kinetic, and internal energies

_______________ is the transfer of energy between a solid surface and the adjacent fluid that is in motion. Multiple choice question. Conduction Convection Radiation

convection

The electrical power equals to the square ____________________ of the multiplying the resistance. (Use a single word to fill the blank.)

current

True or False: All isothermal processes are adiabatic.

false

True or False: Global warming means some form of net energy has been created. (true or false)

false

True or False: Heat and work are point functions.

false

True or False: Heat transfer from a system is positive

false

The conservation of energy principle is also known as an expression of the ______.

first law of thermodynamics

The conservation of energy principle is also known as an expression of the ______. Multiple choice question. zeroth law of thermodynamics first law of thermodynamics second law of thermodynamics

first law thermodynamics

Work is the energy transfer associated with a ____________________ acting through a distance.

force

An adiabatic process is one in which there is no ______. Multiple choice question. temperature change heat transfer pressure change insulation

heat transfer

The sum of all microscopic energy is called _____________________ energy.

internal

From the list below, select all of the following that represent units for a rate of heat transfer. (Check all that apply.) Multiple select question. Calorie Btu/lbm kW Btu/h

kW, Btu/h

In the absence of magnetic, electric, and surface tension effects, the total energy of a system consists of the ______________ , ______________________ , and ________________ energies.

kinetic, potential and internal

The internal energy that is required to undergo a phase transition and is associated with the binding forces between the molecules of a substance is called ____________________ energy.

latent

For linear elastic springs, the displacement of the spring is ______ to the force applied. Multiple choice question. quadratically proportional linearly proportional inversely proportional nonlinearly proportional

linearly proportinal

Total energy of a system can be classified in two groups: __________________ and ______________________.

macroscopic and microscopic

Which of following energy is not microscopic? Multiple choice question. Chemical energy Latent energy Sensible energy Nuclear energy Mechanical energy

mechanical energy

Efficiency can be expressed in terms of the desired _____________ divided by the required ________________.

output, input

The energy that a system possesses as a result of its elevation in a gravitational field is called _____. Multiple choice question. chemical energy kinetic energy magnetic energy potential energy electrical energy

potential energy

The electrical power is defined by the product of the __________________difference and the electric ___________________ .

potential, current

__________________________ is the transfer of energy due to the emission of electromagnetic waves (or photons). Multiple choice question. Radiation Conduction Convection

radiation

The atoms of polyatomic molecules rotate about an axis, and the energy associated with this rotation is ________________________kinetic energy

rotational

The portion of the internal energy of a system associated with the kinetic energies of the molecules (molecular translation, rotation, vibration, electron and nuclear spin, and electron translation) is called the _________________ energy.

sensible

During a process, if the state of the system does not change, the system energy will ______. Multiple choice question. increase be equal to zero stay the same decrease

stays the same

Heat is a form of energy transfer by virtue of a ________________________ difference.

temperature

The power transmitted by a shaft is proportional to the ____________ and the ___________________ speed.

torque, rotational

True or False: Following the formal sign convention, work done by a system (or work output) is defined as positive.

true

True or False: If it is not heat, the energy crossing the boundary of a closed system must be work.

true

True or False: Work is a form of energy interaction, and thus it is allowed to cross the boundary of a control volume.

true

True or false: Two aluminum spheres with the same mass are located at different elevations. The sphere located at a higher elevation will possess greater potential energy.

true

If a closed system is adiabatic, the only possible energy transfer is ______. Multiple choice question. energy transfer by mass flow work heat

work

Power is defined by the _____________________________ done per unit __________________________ .

work,time