wù / lǐ / kè / shàng / lǎo / shī / yǎn / shì / le / luò / tǐ / de / zì / yóu / xià / luò / yùn / dòng

物理课上，老师演示了落体的自由下落运动。

In physics class, the teacher demonstrated the free fall motion of a falling body.