2 sentences for 重心 (zhòng​xīn — center of gravity)

1. 由于重心不稳，这个瓶子倒了。

   yóu​yú zhòng​xīn bù wěn, zhè gè píng​zi dǎo le.

   The bottle fell over because its center of gravity was unstable.

   Source: Dong Chinese Dictionary

2. 三角形的三条中线交于其重心。

   sān​jiǎo​xíng de sān tiáo zhōng​xiàn jiāo yú qí zhòng​xīn.

   The three medians of a triangle intersect at its centroid.

   Source: Dong Chinese Dictionary