如图所示，为某一装置的俯视图，PQ、MN为竖直放置的很长的平行金属薄板，两板间有匀强磁场，它的磁感应强度大小为B，方向竖直向下，金属棒AB搁置在两板上缘，并与两板垂直良好接触，现有质量为m、带电量大小为q，其重力不计的粒子，以初速度v₀水平射入两板间．问：

(1)金属棒AB应朝什么方向、以多大的速度运动，可以使带电粒子做匀速运动？

(2)若金属棒运动突然停止，带电粒子在磁场中继续运动，从这刻开始位移第一次达到mv₀/(qB）时的时间间隔是多少？（磁场足够大）

Routing protocols use different techniques for assigning ______ to individual networks. Further, each routing protocol forms a metric aggregation in a different way. Most routing protocols can use multiple paths if the paths have an equal ______ . Some routing protocols can even use multiple paths when paths have an unequal cost. In either case, load ______ can improve overall allocation of network bandwidth. When multiple paths are used, there are several ways to distribute the packets. The two most common mechanisms are per-packet load balancing and per-destination load balancing. Per-packet load balancing distributes the ______ across the possible routes in a manner proportional to the route metrics. Per-destination load balancing distributes packets across the possible routes based on ______.

A. balancing B. uploadingC. downloading D. transmitting