d's dr =8 依题意 S0=0=0 s1==0 ds ds dt gdt =8t+C dt ds (gt +c)dt s= 28r2+ct+6 将 S1=0=50=0 代入上边两式9=0，C2=0 s0=0=0 1 故所求的路程与时间关系一28r >7 依题意 2 2 0 0 0 0 0 0 t t d s g d t s s s v = =  =    = =   = =   ds d gdt dt = 1 ds gt c dt = + 1 ds gt c dt = + ( ) 2 1 2 1 2 s gt c t c = + + 将 0 0 0 0 0 0 t t s s s v = =  = =     = =  代入上边两式 1 2 c c = = 0, 0 故所求的路程与时间关系 1 2 2 s gt =