PHYS 220 — Lab #7
This lab should only take you a single lab period.
The assignment is
due at the beginning of lecture on
Monday, 6 Apr. In this lab you'll
construct a bisection method (root finder) and a
golden section search (1D optimization), and apply them to various
problems. Your solutions should include 2 function code listings
and a table of numerical results (including respective tolerances)
for each problems.
- Construct a MATLAB bisection method function (to find the a root of
a function) that has the following
inputs/outputs:
- inputs: an interval [a,b], exit tolerance, function handle
- outputs: either a final interval
[af , bf], the final midpoint, or an
interpolated value across the final interval
- In celestial mechanics, Kepler's Equation relates the
mean anomaly M to the eccentric anomaly E of an elliptical orbit of
eccentricity e as:
M = E - e sin(E).
- For M = 1 radian and e = 0.206 (Mercury), 0.0167 (Earth). Calculate the
eccentric anomalies E for each planet.
- Are there values for the eccentric anomaly for which E = M? If
so, what are they.
- In neutron transport theory the critical length of a fuel rod in
a reactor is determined by the roots of this equation: cot(x) =
(x² - 1) / (2x). Determine the smallest positive root of this
equation.
- Construct a MATLAB golden section search function (to find a local
minimum of a function) that
has the following
inputs/outputs (you'll need this for HW #6):
- inputs: an interval [a,b], exit tolerance, function handle
- outputs: either a final interval
[af , bf] or the final midpoint
- Verify that your function works by finding the relative minimum of y =
x³ - 2x² - 4x + 1. (If you can, compare the numerical
result with the exact result.)
- EXTRA CREDIT The Ideal Gas Law, PV = nRT, works
well for low densities since it ignores the size of molecules and
assumes perfectly elastic collisions. A second-order approximation
is the van der Waals (non-ideal gas) Equation of State, which
corrects for finite molecular size and works fairly well even for
densities that are not low. It is given by (P + a(n/V)²)(V -
nb) = nRT, where a is related to the attractive force between
molecules and b is related to the size of each molecule. For P = 3
MPa, T = 300 K and n = 1 mol, find the volume occupied by the two
gasses shown below in both the ideal gas and van der Waals
approximations.
|
Substance
|
a
(J. m3/mole2)
|
b
(m3/mole)
|
| Nitrogen (N2)
|
0.1361
|
3.85x10-5
|
| Freon (CCl2F2)
|
1.078
|
9.98x10-5
|