But the simple answer is, unbalanced force on a body

但简单的答案是， 作用于物体的不平衡力将永远改变物体的速度。

So and unbalanced force doesn't necessarily have to impact the object's speed.

所以和不平衡的力 不一定必须改变响物体的速度。 尽管不平衡力经常会改变物体的速度。所以和不平衡的力 不一定必须改变响物体的速度。 尽管不平衡力经常会改变物体的速度。

It's providing an unbalanced force in a direction opposite it's motion.

水本身的阻力就是运动反方向的不平衡力。水本身的阻力就是运动反方向的不平衡力。

An unbalanced force on an object will not always change the object's direction.

一个不平衡力， 并不一定能改变物体的方向。一个不平衡力， 并不一定能改变物体的方向。

In either of these situations, there must not be any unbalanced force acting on them.

在任何一种情况下或者肯定没有合力。

If I apply an unbalanced force in that same direction-- so that's my force right over there.

如果我在木块运动方向上施加不平衡力在同一方向上。

And so the only way you can actually get this thing to come out of that rest position is if you have a net force, an unbalanced force.

因此, 使物体由静止开始运动的唯一方法就是施加一个非零净力 -- 非平衡力.

So this is not (that is not) true. An object in motion will maintain it's speed and direction forever unless acted on by an unbalanced force.

因此它是不对. 一个运动中的物体永远保持运动速度和方向除非它受到非平衡力的作用.

You can see the cables let go from Tower 4, the platform swinging downward, the support cables crashing through the suspended catwalk, and the top section of Tower 4 breaking off from the unbalanced force of the backstays.

您可以看到缆索从 4 号塔上松开， 平台向下摆动，支撑缆索冲破悬空的过道，4 号塔的顶部因后拉索的不平衡力而断裂。