 
Summary: BUNGEEJUMPING
MATH 2574H, SPRING 2012
UNIVERSITY OF MINNESOTA
INSTRUCTOR: PROF. GREG ANDERSON
Problem
My terminal velocity is 160 ft/sec (twice that of a cat). When I am suspended
motionlessly at the end of a long bungee cord high in the air, I stretch out the bungee
cord 64 ft beyond its natural length. At time t = 0 I am pulled down 16 ft from the
neutral position and then released with zero initial velocity. (Things are arranged
here so that I won't hit the ground, overstretch the bungee, or understretch it.)
(i) Find my position at time t. Choose the coordinate system so that y = 0
corresponds to the height at which I would hang motionless.
(ii) Find the times when I return to the neutral position.
(iii) Find the times when I am at a local maximum or minimum.
Solution
Part (i). The differential equation and initial conditions are
y(0) = 16, y (0) = 0, y +
32
160
y +
