A mass of 2 kilogram is attached to a spring whose constant is 8
N/m, and the entire system is then submerged in a liquid that
imparts a damping force equal to 8 times the instantaneous
velocity. At t = 0 the mass is released from the equilibrium
position with no initial velocity. An external force f(t) =
2U(t−1)*e^(−2(t−1)) is applied.
(a) Write f(t), the external force, as a piecewise function and
sketch its graph.
(b) Write the initial-value problem....