dx dx=vdi dt vat t+ 224)=ao t-+ aot+C2 6 t=O时x=0.C,=0 267 (下一页)2 6 0 0 0 0 2 0 3 2 t a t a x t x c  = + = =  = 则  时 dx vdt dt dx v = ,  = 2 0 2 0 2 0 3 0 2 6 ) 2 ( t c a t a t dt a x = vdt = a t + = + +     （下一页）