Download Session 36 - Iowa State University

Problem Set 36
Session 3, week 12
Supplemental Instruction
Iowa State University
Leader:
Course:
Instructor:
Date:
Noah
Phys 221
Shinar
04/24/2016
1. The compression ratio for a diesel engine in 15:1 (ie the final volume is 1/15 the initial
volume). This compression is adiabatic. The initial pressure is 1 atm, and the initial
temperature is 300 K. Assume that the ratio of heat capacities, γ, for air is equal to that
of O2.
(a) What quantity of heat is transferred between the cylinder and its
surroundings?
(b) What inference about temperature can we make, when we consider the
quantity of heat transferred?
(c) Find the final temperature and pressure of the gas in the cylinder.
(d) If the final volume is 1L, calculate the number of gas molecules involved in
the compression.
2. An ideal diatomic gas originally at 1 atm and 298K undergoes 1) a constant volume
heating to twice the initial temperature 2) an adiabatic reversible expansion back to 298
K.
(a) Draw a PV diagram to model the situation approximately.
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(b) Calculate the total work done between the start and end.
3. Aluminum rivets used in airplane construction are made slightly larger than rivet holes
and cooled by dry ice before being driven. If the diameter of a hole is 4.500 mm, what
should be the diameter of a rivet at 23.0 degrees Celsius if its diameter is equal to that
of the hole when the rivet is cooled to -78.0 degrees Celsius, the temperature of dry
ice? For aluminum, α = 2.4 ∙ 10-5 K-1.
1060 Hixson-Lied Student Success Center  515-294-6624  [email protected]  http://www.si.iastate.edu