Ramp or linearly increasing force p(t)=P t 1 P(t) us(t)1 (uso L4 Po (n)1(1)n 0 0 0 3 t/Tn ▣Response to p(t) 闺 土本程李悦  Ramp or linearly increasing force  Response to p(t)   0 r t p t p t    0 sin n r n r p t t u t k t t          