27.如圖,數(shù)軸上的兩點(diǎn)A、B所對(duì)應(yīng)的數(shù)分別是-10、6.?dāng)?shù)軸上有兩動(dòng)點(diǎn)P和Q,點(diǎn)P從點(diǎn)A出發(fā)向點(diǎn)B運(yùn)動(dòng),到達(dá)點(diǎn)B后立即返回點(diǎn)A,點(diǎn)Q從點(diǎn)B出發(fā)向點(diǎn)A運(yùn)動(dòng),點(diǎn)P的運(yùn)動(dòng)速度是每秒4個(gè)單位,點(diǎn)Q的運(yùn)動(dòng)速度是每秒2個(gè)單位.點(diǎn)P、Q同時(shí)出發(fā),設(shè)運(yùn)動(dòng)時(shí)間為t秒.
(1)數(shù)軸上A、B兩點(diǎn)之間相距
個(gè)單位長度.
(2)當(dāng)點(diǎn)P從點(diǎn)A向點(diǎn)B運(yùn)動(dòng)時(shí),點(diǎn)P所表示的數(shù)是
;在點(diǎn)Q的整個(gè)運(yùn)動(dòng)過程中,點(diǎn)Q所表示的數(shù)是
.(均用含t的代數(shù)式表示)
(3)當(dāng)點(diǎn)P從點(diǎn)A向點(diǎn)B運(yùn)動(dòng)時(shí),若P、Q兩點(diǎn)在數(shù)軸上的點(diǎn)C相遇,求點(diǎn)C所表示的數(shù)是多少?
(4)在整個(gè)運(yùn)動(dòng)過程中,當(dāng)點(diǎn)Q到原點(diǎn)O的距離是點(diǎn)P到原點(diǎn)O的距離的2倍時(shí),直接寫出t的值.