1
4.31 Three masses, kg, kg, and kg, are attached to
springs, N/m, N/m, N/m, and N/m, as
shown. Initially the masses are positioned such that the springs are in their nat-
ural length (not stretched or compressed); then the masses are slowly released
the three masses. ( )
g=9.81;
A=[k1+k2+k3 -k3 0; -k3 k3+k4 -k4; 0 -k4 k4];
4.3476
m
1
m
1
u
1
k
3
k
1
k
2
m12=
m23=
m31.5=
k130=
k225=
k320=
k415=
g9.81=
ms
⁄