The limitations are that you just can’t charge the batteries fast enough to take all the potential energy that’s available in a braking event.
那些限制就是，在一次刹车期间，你只是无法给蓄电池充电充的足够快而取走所有潜在的可以利用的能量。
The limitations are that you just can't charge the batteries fast enough to take all the potential energy that's available in a braking event.
那些限制就是，在一次刹车期间，你只是无法给蓄电池充电充的足够快而取走所有潜在的可以利用的能量。
Even Fortune 500 companies that have long employed lobbyists on other issues have needed to hire more to track potential energy policy changes.
甚至是一直雇佣说客对其他事情进行游说的财富500强公司也需要雇佣更多的人来追踪在能源政策可能发生的可能的变化。
For us right now, the challenge is figuring out how to transform the technology's potential energy into kinetic energy that can fuel successful projects in both the public and commercial sectors.
对于我们来说，现在的难题是解决如何将技术的潜在能量转化成促使公共和商业部门的项目取得成功的动能的问题。
The device has a wave (or swell) pump to pump sea water to a hilltop.It USES the energy of the water in which it floats to pump the stored potential energy.
该设备有一个波浪泵(膨胀泵)能将海水泵送到高处，它利用波浪的能力产生泵送的动力，并将波浪能转化为位能。
The device has a wave (or swell) pump to pump sea water to a hilltop. It USES the energy of the water in which it floats to pump the stored potential energy.
该设备有一个波浪泵(膨胀泵)能将海水泵送到高处，它利用波浪的能力产生泵送的动力，并将波浪能转化为位能。
That is, you minimize potential energy and you see things falling under the force of gravity and so forthgoing to potential energy minima in conformance with this result.
换句话说，你使得势能最小化,然后发现我们关注的东西,在重力或者其他力的作用下下落,直到势能最小的地方,这和我们刚才的结果是一致的。
It means that we better get away from these deterministic models where we have a little electron here with its potential energy and its kinetic energy.
它的意思是我们最好远离，这些确定性模型，那里有一个小电子，它具有势能和动能。
At infinity, there's no stored potential energy, and it drops off more and more negative as one over r.
在无限远处，没有储存的势能，并且它向负方向减少，当距离超过R时。
And so I put potential energy in the spring by pushing them together, and they are lined up now here.
弹簧中储存了能量，把它们挤在一起，它们排列在这里。
Kinetic energy can be converted back to potential energy, can be converted back, - but the sum of them — which we call "mechanical energy" — is conserved.
动能可以转化，成为势能，也可以转化为动能，但是总和-，我们叫做的，机械能，是恒定的。
What is important, of course, if we get the right answer for the gravitational potential energy, that when we move away from this object that the gravitational potential energy increases.
重要的是，如果我们得到了重力，势能的正确值，当我们远离这个物体，重力势能就会，增加。
Okay, my goal was to evaluate for you the gravitational potential energy the way that it is defined in general, not in a special case when we are near the Earth.
好了，我的目标是，用通常的方式，为你们评价重力势能，不是用一个特殊的，接近地球的案例。
Now, what we would like to do is we would like to convert all this gravitational potential energy into kinetic energy of that disk.
现在要做的，就是要转化，所有这些重力势能，变成圆盘的动能。
The force is always opposing the direction of increasing potential energy, so the force will drive it back and so that's why we call this a stable equilibrium.
力一直和势能，增加的方向，相反，作用力会将其推回，那就是为什么称它，稳定平衡的状态。
But you can clearly see that - if I go from here to here — if I take an object - and go from here to here — that the potential energy will increase, and that's all that matters.
但是你能清晰看到，如果从这里移到这里-，拿一个物体，从这儿到这儿-，势能会增加，这就是要考虑的所有。
Now we can calculate what the difference is between the potential energy... the kinetic energy after the collision and the kinetic energy before the collision.
我们可以计算出差别，在储存能量。，与碰撞后动能的差别，还有碰撞前动能。
This is the kinetic energy for something in orbit at this radius, and this is the potential energy.
这是在轨道内这个，半径的物体的动能，这是势能。
When I'm here, gravitational potential energy ; increases in this way; the gravitational force is in this direction.
重力势能，这样增长,重力;,是在这个方向,当我在这里。
Then this will have a positive gravitational potential energy, and this will have one that is higher than this one by this amount.
那么它将是,正的重力势能，这样的话这点,就比另一点高。
You know, if you want to measure the potential energy of something in a gravitational field, you have to define the zero somewhere, right, because it's arbitrary.
你知道，如果你想测量重力场，中某种东西的势能，你需要，在某处定义一个零点，对吧？
Then we have the conservation - of mechanical energy — the sum of kinetic energy and potential energy.
我们知道，机械能守恒定律-，动能和，势能的总和。
If we know the force — in this case, the spring force or in those cases, - the gravitational force — we were able to calculate the potential energy.
在这个例子里-，弹力，或这些例子里，重力，我们能够-，计算出势能，现在问题是。
C at this point c, this has reached a maximum velocity that it can ever have because all the potential energy has been converted to kinetic energy.
在这个点，达到它能达到的，最大动能，因为所有的势能，都转化成了动能。
I can never predict The Times, because if I make the spring more squeezed, then obviously I will have more potential energy.
我无法预测时间，因为弹簧压缩得更紧，这样就储存更多能量。
So you're using, then, the conversion of gravitational potential energy to kinetic energy.
所以你在利用，重力势能，转换成，动能。
The formal definition is that the gravitational potential energy at a point P is the work that I, Walter Lewin, have to do to bring that mass from infinity to that point P.
形式定义就是,它在点P的重力势能,等于我，将物体从无穷远处,移动至点P所做的功。
So what, now, is then the total -- energy of the system-- that is, the sum of the kinetic energy plus the potential energy?
所以现在系统内,总能量是多少-,是动能和,势能之和吗？
So what, now, is then the total -- energy of the system-- that is, the sum of the kinetic energy plus the potential energy?
所以现在系统内,总能量是多少-,是动能和,势能之和吗？
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