把干净的玻璃板吊在弹簧测力计的下面,记下测力计的读数。如上2

把干净的玻璃板吊在弹簧测力计的下面,记下测力计的读数。如上2图让玻璃板的下表面接触水面,然后稍稍用力向上拉,发现弹簧测力计读数变大,其原因是玻璃板与水的接触面之间存在

A.摩擦力    B.分子引力    C.分子斥力   D.大气压力

答案

B

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