另一片往这个方向飞，质量为m1，速度为v1。

And another piece flies off in this direction with mass m1, with velocity v1 prime.

youdao

长天一片澄蓝，碧绿的庄稼上云雀凌空穿飞。

The sky was blue, the larks was soaring high over the green corn.

youdao

长天一片澄蓝，碧绿的庄稼上云雀凌空穿飞。

The sky was blue, the larks was soaring high over the green corn.

youdao