如圖①,等邊△ABC中,AB=6cm,點(diǎn)O在BC上,且OB=2cm,動(dòng)點(diǎn)P從點(diǎn)A出發(fā)沿射線AB以1cm/s速度運(yùn)動(dòng),連接OP,將線段OP繞點(diǎn)O順時(shí)針旋轉(zhuǎn)60°得到線段OD,設(shè)點(diǎn)P運(yùn)動(dòng)的時(shí)間為t(s).
(1)用含t的代數(shù)式表示BP的長.
(2)如圖②,當(dāng)點(diǎn)D落在AC邊上時(shí),求證:△PBO≌△OCD.
(3)當(dāng)OD平行于△ABC的一邊時(shí),直接寫出t的值.
(4)作點(diǎn)D關(guān)于點(diǎn)O的對(duì)稱點(diǎn)E,當(dāng)t=
10
10
秒時(shí),點(diǎn)E恰好落在射線AC上.
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