题干

如图所示,烧杯的底面积是200cm2,里面装有一定量水(图甲),水面在A处,用弹簧测力计吊着未知物体,先将物体浸没在水中(图乙),水位升高到B处,示数是18N;再将物体缓慢提出,使水位下降到AB的中点C处,示数是23N(不计物体带出的水).(g取10N/kg),下列判断中正确的是(   )

①物体的质量是2.8kg;

②物体的体积是1×10﹣3m3;

③物体浸没时受到的浮力是15N;

④从乙到丙,水对烧杯底面的压强减小了250Pa.

A:只有①、④正确

B:只有②、④正确

C:只有①、②、④正确

D:①、②、③、④全正确

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答案(点此获取答案解析)

C

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