Fall wk 2 – Thus.7.Oct.04

• Welcome, roll, questions• Thermal physics• break• continue Calculus Ch.1• Looking ahead

Energy Systems, EJZ

Discuss Ch.18, Thermal physics

• Key points?

• Insights from team discussion?

• Questions?

- questions of fact: Can we find answer in the text? What page?

- Outstanding questions of fact

- Outstanding significant questions

Thermal Physics - outline

• Temperature

• Heat = energy

• Discuss examples

• Absorption of heat by solids and liquids

• Work done by a gas (more next week)

• Practice: conceptests and HW

Temperature

TC = T – 273 ° TF = 9/5 TC + 32°

ConcepTest 16, 18, 19

Heat = energy

Energy = work = force * distance

Force = Mass * Acceleration

Acceleration = rate of change of speed

Speed = distance / time

units of Speed (m/s)

units of Acceleration (_____)

units of Mass (kg)

units of Force (______) = (Newton) = (N)

Units of Energy:

Heat = energy: unitsUnits of energy or work: Joules = Newton * meter

In fundamental SI units of space (m), time (s), and mass (kg):

SI energy units (J) =

CGS units: space (cm = 10-2 m), time (s), and mass (g = 10-3 kg):

CGS energy units (erg) =

What other units have you encountered for energy?

cal = 4.1868 J, kcal = _______, cal = 4 x 10-3 BTU

BTU = ________ Joules? ConcepTest 38

Absorption of heat by solids and liquids

Thermal equilibrium: if TB = TA and TC = TA then TC = TB

Heat Capacity: Q = C T

Specific Heat: Q = c m T

Heats of transformation: Q = L m

boiling or condensing: LV; Freezing or melting: LF

ConcepTests: TE 1,3; C 40-42 ; L 53, 54, 60

Problems

Work done by a gas (CT 3, 64, green)

Work done = pressure * volume = area under curve (clockwise)

Heat added = work done + change in internal energy of gas

Thermal Physics HW

Questions: #3 (Lf), 6 (cycle), 8 (radiation)

Candidate problems:

Ch.18.5: #4 (C,F), 5 (conversion)

Ch.18.8: #24 (diet), 26 (butter), 27 (watts), 28 (garage), 29 (water heater BTU), 32 (cooling), 33 (solar heater), 35 (cooling gas)

Additional: #73 (work), 80 (solar house), 85 (transformations), 94 (radiation)

We will choose (in class) half of these to be due next week, and half for the following week.

Calculus - outline

• Q about today’s HW

• Review 1.1-1.3

• Practice with logarithmic functions

• 1.4 Trig review

• Wiley says they have fixed eGrade – please see if your registration works

• If eGrade doesn’t work for you yet, hand in paper homework for now.

Calc 1 HW 2

Homework due next Thus: Ch.1.4 # 1, 14, 18, 26, 35Ch.1.5 # 1, 14, 16, 20, 29, 31, 34, 36, 40Ch.1.6 # 2, 4, 8, 14, 18, 23, 28

Recommendations: – Work odd problems for practice first, since you have

their solutions– Work due problems on scratch paper first, then input

electronically for detailed feedback

Discuss:– Shorten assignments, stretch syllabus?– Teamwork on homework– Qualitative reasoning center

Looking ahead

• Seminar in Sem II C2109 tonight• Please put your team’s best Q on the board before

5:00• Tomorrow:

– Post your research assignment individually

– One-page essay about your learning this week?

– TA Brian Orr available in QRC Friday 10am - noon

• Next week: – TA available in homeroom Wed 1-3

– visitors will discuss sustainability and solar panels on Tuesday and Wednesday

ConcepTests: Temperature & Heat

ConcepTests: Temperature & Heat

Thermal Equilibrium ConcepTests

Specific / heat / capacity ConcepTests

Heat of transformation ConcepTests

80

Work done by gas ConcepTests

Preview of powerPower = rate of doing work = energy / time

SI units of Power: Watts = Joules/sec = ____

Horsepower = 1 hp = 550 ft * lb/s = 746 Watt

What is a kilowatt-hour?

A. Power

B. Energy

C. Other