Name:
ME 220a.01 Thermodynamics I
Midterm Exam II
There are four problems. Try to attack each problem since the problems are NOT arranged according
to their difficulties.
Problem 1. Fundamentals of th
Announcements
Midterm #2: in-class, Tuesday (04/01) at 8:10 AM
Additional office hour: Monday (03/31) at
3:00-4:30 PM
Policy: the same as midterm I
Thermal Reservoirs and Heat Engines
Thermal Energy R
0tIA,'+t ts^
Name:
ME 220 A.01 Thermodynamics I
Midterm Exam 2
Problem 1. Fundamentals of thermal efficiency, coefficient of performance, and reversible
steady-flow work. (15 points)
(a) An inventor c
1515.9 An egg is dropped into boiling water. The amount of heat transfer to the egg by the time it is cooked
and the amount of entropy generation associated Twith this heat transfer process are to be
139 An insulated rigid tank contains a saturated liquidvapor mixture of water at a specified pressure. An
electric heater inside is turned on and kept on until all the liquid Ttaporized. The entropy c
Name: 5-b C ct+^ rn1
ME 220a.01 Thermodynamics i
Midterm Exam 1
There are four problems. Try to attack each problem since the problems are NOT arranged according
to their difficulties.
Problem 1. Comp
(b) Heat Pumps are preferred than direct electric resistance heaters since they Will save energy. If
a house needs an electric resistance heater to produce 1200 kWh to keep warm in a winter
month. how
531 Air is accelerated in a nozzle from 30 m-"s to 131] The mass ow rate, the exit temperature, and
the exit area of the nozzle are to be determined.
Assumptions 1 This is a steady-ow process since th
Name: SO l WH O11
ME2203.01 Final Exam
Spring 2007
Problem 1. Answer each question concisely. (total: 18 points)
(a) Fill out the following table for water. Find the quality only when it is applicable
HW#3 Solution
1. A pistoncylinder device contains 0.15 kg of air initially at 2 MPa and 350C. The air is first
expanded isothermally (temperature is constant) to 500 kPa, then compressed polytropicall
System, Surroundings, and Boundary
A THERMODYNAMIC SYSTEM (SYSTEM), is defined as a quantity of
matter or a region in space chosen for study.
Everything external to the system is considered to be part
'.-'-1 15. Liquid. Twater is to be plunped b)? a 25-kW pump at a specied rate. The highest pressure the water
can be pumped to is to be determined.
Assumptions 1 Liquid Twater is an incompressible sub