m,l M(t)=M_(0)cos\omega t. Accordingly, obtain the differential equation
of the small amplitude vibrations of the system and calculate
the forced vibration amplitude. consider the wieght of the bar and and point mass M
M=4kg,m=3kg,k=28(N)/(m),c=14k(g)/(s),\alpha =0.6,l=1m
M_(0)=6Nm,\omega =10ra(d)/(s),g=10(m)/(s^(2))