It was a potent weapon that could be swung from side to side.

这是一种强有力的武器能够从一边摆到另一边。

Why did their ponytails swing from side to side like that?

为什么他们的马尾辫会那样左右摆动？

B) How far the tail could swing from side to side.

B) 尾巴可以左右摆动多远。

It's stiffened by lots of bony rods that run along the length of the tail that would have had a lot of force behind it when it was swung from side to side.

它被许多沿着尾巴方向延伸的骨棒加固，当它左右摆动时，尾巴后面会产生很大的力。