A:should succeed , was put
B:succeeded , put
C:should succeed, be put
D:succeeded , be put
He has ______ for some years, but his _____ still makes us very sad now.
如图所示,水平桌面上放一个重2N,底面积为60cm2的杯子,杯内盛有20N的水,水深30cm,求:
(1)水对杯底的压力和压强;
(2)杯子对桌面的压力和压强.