Chapter 2 Energy

Question 1

what is energy?

Answer 1

Definition from the Oxford English Dictionary – “The ability or capacity to produce an effect.”

For example, a substance with energy can move, do work, or heat some other substance.

It was shown (experimentally by Joule) that energy is a property.

Question 2

For our purposes, we will divide the energy of the substance into three parts:

Answer 2

Internal energy

Kinetic energy

Potential energy

Question 3

Potential energy

Answer 3

Question 4

kinetic energy

Answer 4

Question 5

Internal energy

Answer 5

Question 6

Total Energy

Answer 6

Question 7

Transport of Energy

Answer 7

Changes in the state of the system either involve changes in the form of energy within the system (e.g. kinetic energy being converted to internal energy) or

transferring energy from one substance to another, including into or out of the system

Question 8

3 Ways energy can be transported

Answer 8

Ways energy can be transported

Heat transfer

Work

Mass flow

Question 9

Transport of energy via heat transfer is the movement of energy caused by a__________.

Answer 9

Transport of energy via heat transfer is the movement of energy caused by a temperature difference.

Question 10

The three mechanisms by which heat transfer occurs

Answer 10

the three mechanisms by which heat transfer occurs

Conduction

Convection

Radiation

Question 11

Conduction is the transfer of energy ____?

Answer 11

Conduction is the transfer of energy from the more energetic particles of a substance to the adjacent less energetic ones as a result of interaction between particles.

An example is heat conduction through a metal spoon from hot water to a person’s hand.

Question 12

Convection is the transfer of energy between a solid surface and the _____?

Answer 12

Convection is the transfer of energy between a solid surface and the adjacent fluid that is in motion, combining conduction and fluid motion.

Convection is responsible for the increased heat transfer associated with “wind chill factor.”

Conduction through still air is slow, but fluid motion maintains a strong temperature gradient, driving high rates of heat transfer in convection.

Question 13

Convection equations

Convection can often be taken into account using Newton’s law of cooling

Answer 13

Question 14

Radiation is the transfer of energy due to the emission and absorption ____?

Answer 14

Radiation is the transfer of energy due to the emission and absorption of electromagnetic waves (or photons).

The heat transfer is highly dependent on the temperature of the object, as can be seen in the Stefan-Boltzmann law, which describes the maximum rate of heat transfer from a surface at temperature Ts by radiation