The illusion works with mechanical force, call it friction, wearing away at the sensibility.
感觉上，这幻象以机械的力量，所谓的摩擦力、磨损的物理力量运作著。
ZA27 alloy shows good mechanical properties and working properties. Small coefficient of friction and large sticking force to oil can substitute ZA27 alloy for Bronze alloy.
ZA27合金具有良好的力学性能和加工性能，它的摩擦系数小，对油的亲和力大，而且ZA27合金的综合性能突出。
From the common mechanical phenomenon, present a theoretical method on how to judge the direction of static friction force.
本文以常见的力学现象为例，从理论上阐述判断静摩擦力方向的方法及作功问题的证明方法。
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