te law of inertia can't be proved by experiments. Reason: a free particle or system; no interaction; an inertial frame of reference Logical cycle appears Galilean ideal experiment Therefore the law of inertia is regard as the principle of inertia( a sort of hypothesis )目 录 第2 章 The law of inertia can’t be proved by experiments. Reason： • a free particle or system; • no interaction; • an inertial frame of reference; Logical cycle appears Galilean ideal experiment; vo v6 = vo Therefore, the law of inertia is regard as the principle of inertia ( a sort of hypothesis)