26.如圖1所示,矩形ABCD中,∠ABC=90°,AB=8cm,BC=6cm.動(dòng)點(diǎn)E從點(diǎn)A出發(fā),沿對(duì)角線AC以每秒2cm的速度向終點(diǎn)C運(yùn)動(dòng),連結(jié)DE,作點(diǎn)A關(guān)于DE的對(duì)稱點(diǎn)F,連結(jié)EF、DF,設(shè)點(diǎn)E的運(yùn)動(dòng)時(shí)間為t秒.
(1)AC=
cm,DF=
cm.
(2)如圖2,當(dāng)E運(yùn)動(dòng)到使DF∥AC時(shí),求t的值.
(3)當(dāng)點(diǎn)F落在△ACD內(nèi)部時(shí),求t的取值范圍.