1.引言 在高中物理中,学习机械能守恒时,常常会遇到下面的一个典型题目:如图所示,一个在竖直平面内的光滑轨道,假定质点a从A点沿轨道下滑,而质点b在圆心O点自由落体,初速度均为零,求:(1)到达地面P点时,质点a的速度;(2)质点a和质点b哪一个先到P点?
HepcoMotion ? ALR Aluminium Rings HepcoMotion ALR aluminium rings run with Bishop-Wisecarver DualVee polymer guide wheels. The system provides a cost-effective rotary movement for medium precision, lightly loaded applications. The rings are made from anodised aluminium and the wheels are made with a polymer outer form moulded onto a stainless steel bearing and stud. The system is therefore sui