26.如圖在長(zhǎng)方形ABCD中,AB=12cm,BC=8cm,點(diǎn)P從A點(diǎn)出發(fā),沿A→B→C→D路線運(yùn)動(dòng),到D點(diǎn)停止;點(diǎn)Q從D點(diǎn)出發(fā),沿D→C→B→A運(yùn)動(dòng),到A點(diǎn)停止.若點(diǎn)P、點(diǎn)Q同時(shí)出發(fā),點(diǎn)P的速度為每秒1cm,點(diǎn)Q的速度為每秒2cm,用x(秒)表示運(yùn)動(dòng)時(shí)間.
(1)求點(diǎn)P和點(diǎn)Q相遇時(shí)的x值.
(2)連接PQ,當(dāng)PQ平分矩形ABCD的面積時(shí),求運(yùn)動(dòng)時(shí)間x值.
(3)若點(diǎn)P、點(diǎn)Q運(yùn)動(dòng)到6秒時(shí)同時(shí)改變速度,點(diǎn)P的速度變?yōu)槊棵?cm,點(diǎn)Q的速度為每秒1cm,求在整個(gè)運(yùn)動(dòng)過(guò)程中,點(diǎn)P、點(diǎn)Q在運(yùn)動(dòng)路線上相距路程為20cm時(shí)運(yùn)動(dòng)時(shí)間x值.