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Unformatted text preview: Stevens Institute of Technology
E234 - Thermodynamics
Sections A, B, C, D: Tuesday, January 27, 2009
There will be a quiz at the end of the recitation. The quiz will cover the material listed
under the learning objectives.
You should be able to:
1. Define the key terms in the class notes on WebCT
2. Use S.I. units, especially W, kWh, J, Pa, N, K
3. Know units of pressure: Pa, mmHg, bar, atm and conversion from one to the other
4. Convert temperature from one scale to another in oF, oC and K
Reading and Study Assignment:
1. Chapter 1 to section 1-9;
2. Lecture notes – Module 1 until slide 42 "Units of pressure"
1. Please write the correct answers:
a. 182 oF =
83.3 oC = 356.5 K
b. 0.1 atm = 76 mmHg = 10.1325 kPa c. 1 liter = 0.001 m3 = 1000 cm3
2. A 1.5-kW electric resistance heater in a room is turned on and kept on for 20 min.
What is the amount of energy transferred to the room by the heater in J? in kWh? 3. Separate the list P (pressure), F (force), V (volume), v (specific volume), ρ
(density), C (color), T (temperature), m (mass), L (length), t (time), and V (velocity) into intensive, extensive, and non-properties.
Intensive: P (pressure), v (specific volume), ρ (density), C (color),
Extensive: V (volume), m (mass)
Non-property: F (force), L (length), t (time), and V (velocity)
4. A pressure cooker of volume 10 liters is filled with 5 kg of liquid water and 5
liters of steam with a specific volume of 0.2 m3/kg. Determine
a. The density of the water in SI fundament Fall 2008 b. The mass of the steam in grams
c. The specific volume of the system (liquid water + steam)
5. If my base metabolic rate is 100 W and is added to the energy I burned when I
exercised this morning for 30 min and used up 400 Calories, how much total
energy did I burn (in J and in kWh)? What was my average power (in W) during
Note: The great calorie "Calorie" is the unit used to measure food (caloric) intake.
We need between 2000 and 3000 calories per day depending on weight, age,
level of activity and other factors.
1 Calorie = 1000 calories = 4180 J
Assuming 2500 Calories, the base metabolic rate (averag power expanded) would
(2500x4180)/24x3600 = 121 W
The brain uses about 20% of this power, so does the liver, etc..
1) Total energy 2) Average power Fall 2008 ...
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- Spring '09