COSC1001/1901 (Semester Two, 2010) Exam Solutions and Marking Scheme
Computational Science in MATLAB
COSC1001 (Normal) & COSC1901 (Advanced)
Exam Solutions and Marking Scheme
1. Measuring acceleration due to gravity
This question assesses week 8 (“Review the application of linear algebra to physical prob-
lems”, “Understand the built-in matrix manipulation functions” and “Apply matrix methods
to problems in linear algebra...”), week 3 (“Write user-defined functions”), week 4 (“Under-
stand the matrix datatype”) and week 7 (“Calculate the accuracy of statistics drawn from
limited populations”)
(a) (3 marks)
0.072g+ 0.07b+c= 0 (1)
0.532g+ 0.53b+c= 2 (2)
0.852g+ 0.85b+c= 6 (3)
0.0720.07 1
0.5320.53 1
0.8520.85 1
g
b
c
=
0
2
6
(4)
(b) 3 marks
>> A=[0.07^2 0.07 1; 0.53^2 0.53 1; 0.85^2 0.85 1];
>> y = [0; 2; 6];
>> gbc = inv(A)*y
(c) 2 marks
function g = calcg(t)
% This function computes the acceleration due to gravity, based on
% an experiment that includes sensors placed at 0, 1 and 2 m
A=[t(1)^2 t(1) 1; t(2)^2 t(2) 1; t(3)^2 t(3) 1];
gbc = A\[0; 2; 6];
g=gbc(1);
(d) 2 marks
disp([’g = ’ num2str(mean(g)) ’ +/- ’ num2str(std(g)/length(g))])
1
