The repetition of the ultrasonic sound and the experiment of zero velocity in gas flowmeter are tested using this speed measurement system.
利用该测速系统，进行了超声波的重复性测试，以及在以空气为介质的零流实验。
Just to be clear, the jumper velocity (and thus kinetic energy) of the jumper at the top and the bottom are both zero.
我来解释一下，整个跳楼过程中，跳楼者的速度（由此便产生了动能）在起跳处和着地处都为零。
Clearly, here the velocity is zero.
显然，这里的速度就是。
The angular velocity is zero when you release it and is a maximum when it goes through the lowest point.
角速度是,当你释放它的时候,当它到达最低点,速度达到最大。
Here the velocity is increasing so the acceleration must 0 be larger than zero here.
在这里速度在增加，所以加速度，肯定大于。
If the total energy when you leave the Earth with that velocity 0 if the total energy is larger than zero, you do better than that.
如果当你以那速度，离开地球的总能量，大于，对你就更容易了。
Again, if I had changed the zero points you would have found the same values for the average velocity.
再强调一次，不管我这个0点选在哪里，这个平均速度的值，都是不会改变的。
the position of the highest point P we first ask ourselves the question from equation number four: 0 when is the velocity in the y direction zero?
为了找到最高点P的所在,我们首先得,解答我们刚才提出的问题：,究竟何时y方向上的速度减为？
If it starts going in this direction 0 the velocity must be less than zero -6 and indeed it is, it's minus six.
如果它向这边移动,那么速度一定小于,毋庸置疑，是。
We define average velocity as the position at time four seconds minus the position at time zero, 4 divided by four.
我们定义平均速度，是四秒时的位置，减去0秒时的位置，除以。
Make v2 zero, and you see exactly that you see here the same result, so this must be the velocity of the center of mass.
使v2为，你显然知道,在这里有同样的结果，它必然是重心速度。
So the average speed 5m/s is 4.5 meters per second, 0 but the average velocity is zero.
因此平均速率,是4。,但是平均速度是。
The object starts out at t equals zero with a negative velocity.
物体从t=0时开始运动,其速度为负。
Otherwise my velocity in this direction 0 could never become zero.
否则我的速度,不会变到。
The zero of kinetic energy is 0 when the object has no velocity, because kinetic energy So if the object has no velocity, then there is no kinetic energy.
物体没有速度时,动能为，因为动能,如果物体没有速度，就没有动能。
So if we now look at this plot we can search for The Times that the velocity is zero so you have to look for the derivative being zero.
我们观察一下这个图像，就可以找到，速度为0的时刻，因此只需要观察，导数为0的情况。
And at time zero, when it is there, it has a velocity in that ellipse.
时间为0时，在轨道上有速度。
x Xo must be x zero-- - which I conveniently choose zero-- plus 133 meters per second, which is the velocity in the x direction, which never changes.
回到这个点的时候，x，then，when，it，is，back，at，this，point，肯定是-,为了方便我用0表示-,加上133米每秒，这是X方向的速度，它没有变过。
Therefore, their velocity was zero, which clearly wounded the team's collective pride.
因此，他们没有取得任何进展，这明显的伤害了该团队的集体自豪感。
However, if you take the average acceleration t1 0 that is smaller than zero 0 because here the velocity is zero but here the velocity is negative.
可是如果考虑到,和t5之间的平均加速度5，between，t1，and，t5,那么它将小于,因为这里速度为,但是到了这里却是负值。
So the signs in the velocity and the signs in average acceleration depend crucially on how I have defined my increasing value of x not where I choose my zero points.
所以速度的符号,和平均加速度的符号,这二者都取决于,这里x正方向,是如何定义的,和0点的选取没有关系。
Well, before, the speed is zero and so the momentum is zero. And there comes the bang and one piece flies in this direction with a certain velocity, v2 prime.
在之前，速度为，动量也为0，现在砰响了一声，一片朝这个方向飞，它的速度为v2。
Now, I would think that it is reasonable to ask the following question: What is the average velocity, for instance, between time zero and time four?
现在，我认为,提出如下问题,是十分合理的：,比如说，平均速度是多少，在0到4秒之间？
So those are the times that the velocity is zero.
所以这些,就是速度为0的点。
That is the velocity at time zero, 0 and this is zero.
就是初始速度，而第二项是。
t2 In our case, t1 to t2 here 0 notice the velocity is zero as a start.
请看我们的例子里的t1和,请注意初始速度为。
Liquid velocity is near zero at the pipe wall and increases to maximum at the pipe center.
在管壁处液体速度近似为零，并在管中心处达到最大。
For the case of planar interception, the so called relative heading error angle between the relative velocity vector and the LoS (Line of Sight) is chosen as the output to be controlled to zero.
针对平面拦截问题，选择导弹和目标之间的相对速度矢量与导弹-目标视线之间的夹角（称为相对航向误差角）作为将要被控制到零的输出。
In order to keep the divergence of velocity being zero, a special treatment of divergence term in Poisson equation is proposed.
为使速度散度保持为零，在泊松方程中给速度散度一个特殊的处理。
Second, the free-boundary is handled by using combination of the zero-velocity method with the general ghost-image method and fourth-order difference format is used in free-boundary.
然后采用将零速度法和广义虚像法相结合的方法来处理自由边界，并在自由边界上采用四阶精度差分格式；
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