24.長(zhǎng)方形ABCD中,AB=6,AD=m,點(diǎn)P以每秒1個(gè)單位的速度從A向B運(yùn)動(dòng),點(diǎn)Q同時(shí)以每秒2個(gè)單位的速度從A向D運(yùn)動(dòng),點(diǎn)E為邊CD上任意一點(diǎn).
(1)當(dāng)m=8時(shí),設(shè)P,Q兩點(diǎn)運(yùn)動(dòng)時(shí)間為t,
①若Q為AD中點(diǎn),求t的值;
②連接QE,若△APQ與△EDQ全等,求DE的長(zhǎng).
(2)若在邊AD上總存在點(diǎn)Q使得△APQ≌△DQE,求m的取值范圍.