Let us, for the sake of simplicity, call the mass determined in the first way the inertial mass and that determined in the second way the gravitational mass.

为简便起见，我们把用第一种方法所测定的质量叫做惯性质量，而把用第二种方法所测定的质量叫做引力质量。

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One way is to try and falsify the equivalence principle, to show that the two phenomena of gravitational and inertial mass are not really identical.

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