Previously, it was just you and the boat

一开始你和船构成一个系统
and you couldn't change your total momentum.

整体的动量不能改变
But the ground is now pushing you,

但是现在大地给你一个推力
and it's obviously pushing you to the right

显然方向是向右的
because you were flying to the left and you were stopped.

因为它阻止了你向左的飞行
So, your combined system, you and the boat,

所以整个系统你和船这个整体
have a rightward force

受到了一个向右的力
acting for the time it took to stop you;

其作用的时间就是使你停止运动的时间
it's that momentum that's carried by the boat.

这就是使船运动的动量
A better way to say this is, you and the boat exchange momenta,

一种更好的解释方法是你和船交换了动量
you push the boat to the right, you move to the left,

你给船一个向右的力你向左运动
and your momentum is killed by the shore.

你的动量受到大地的作用减为 0