2.在?ABCD中,AB=3cm,AD=5cm,BD=4cm,動(dòng)點(diǎn)P從點(diǎn)D出發(fā),以4cm/s的速度沿折線DC-CB-BD運(yùn)動(dòng),連接AP交BD于點(diǎn)O,設(shè)點(diǎn)P的運(yùn)動(dòng)時(shí)間為t秒.
(1)當(dāng)點(diǎn)P在DC邊上運(yùn)動(dòng)時(shí),直接寫出DP、CP的長.
(2)在(1)的條件下,當(dāng)△OPD是等腰三角形時(shí),求t的值.
(3)當(dāng)點(diǎn)P在AD的垂直平分線上時(shí),求出此時(shí)t的值.
(4)點(diǎn)Q與點(diǎn)P同時(shí)出發(fā),且點(diǎn)Q在AB邊上由點(diǎn)A向點(diǎn)B運(yùn)動(dòng),點(diǎn)Q的速度是1cm/s,當(dāng)直線PQ平分?ABCD的面積時(shí),直接寫出t的值.