运动定律 yùndòngdìnglǜ laws of motion Origin Definitions Defs Strokes Stroke Words Sentences Sents 牛顿第一运动定律 niúdùndìyīyùndòngdìnglǜ Newton's first law of motion the fundamental law of physics stating that an object at rest stays at rest and an object in motion stays in motion unless acted upon by an external force