a5_cee3804_2011 - CEE 3804 Computer Applications in Civil...

CEE 3804: Computer Applications in Civil Engineering Spring 2011
Assignment 5: Matlab Operations
Date Due: March 29, 2010 Instructor: Trani
Problem 1
Use Matlab to solve this problem
A person wearing a parachute jumps from a hovering helicopter at 3,000 meters above ground.
Task 1
Neglecting the lateral speed component of the parachutist, calculate the distance traveled (d) and the vertical speed (v) as a
function of time (t) according to the following equation:
speed = v0 * exp (-cd / m * t) + g*m/cd *(1- exp (-cd /m * t));
distance = g*t / (cd / m) - g/ (cd / m).^2 .* (1- exp (- cd / m * t)) + v0/( cd / m) .* (1- exp (- cd / m * t));
where: the parameters m, cd, m, vo and g are defined as follows:
g = 9.81; % acceleration of gravity (m/s-s)
cd = 12.5; % drag factor (kg/s)
m = 68.1; % mass of the person (kg)
v0 = 0; % initial speed (m/s)
t = time in seconds
Create a regular Matlab script to estimate and plot the speed and distance traveled by the parachutist from the moment of the
jump to a point in time 15 seconds after the jump.
Task 2
Use the Matlab subplot command to plot both speed and distance on the same figure. Plot and label accordingly.
Task 3
Suppose the parachutist opens the parachute 9 seconds after the jump. At that time, the drag factor (cd) increases tenfold.
Modify your script to estimate the new velocity and distance traveled. Make plots.