PHYS 220 — Lab #6
In this lab you will again work as individuals, but discussions are OK.
The assignment is
due at the beginning of lecture on
Monday, 30 Mar. In this lab you'll explore the properties of
curve-fitting algorithms. You'll need to submit your codes, plots and
answers to the questions, below.
- For this problem, you'll need the data
set lab6_1.mat.
These represent velocity (m/s) data from an acoustic ranging device as a
function of time (s). Use the normal equations method to determine the
best fit line for the model equation v = vo + at.
- Plot the raw data and a best-fit line on the same axes.
- State the values determined for vo and a.
- Determine the uncertainties in those parameters.
- Describe a physical experiment that might produce these data.
- For this problem, you'll need the data
set lab6_2.mat.
These data represent the signal voltage (V) across a circuit element as
a function of
time (s). Use the normal equations method to determine the
best fit curve for the model equation s = Asin(t) + Bsin(2t) + Csin(3t).
- Plot the raw data and a best-fit curve on the same axes.
- State the values determined for A, B and C.
- Determine the uncertainties in those parameters.
- Look at your result for B. What change could you make to your
model equation based on this result.
- For this problem, you'll need the data
set lab6_3.mat and my
code expFit.m.
In a lab you have a sample of 116Xe gas. You have a
device to determine the amount of that particular isotope present
and let it run for a few seconds prior to t = 0 (all t data are in s; N are in # of 116Xe atoms). 116Xe
gas naturally decays and you're trying to determine the half-life.
- What is the half-life of 116Xe according to your data?
- Did your lab technician properly set up your equipment? Use your
fitted parameters to justify your answer.