Relative towards the block, for instance, the piston of a reciprocating motor is constrained with the cylinder to move over a straight path; factors around the crankshaft are constrained by the most crucial bearings to move on circular paths; no other forms of relative motion are feasible. 像小米电视已经限制U盘安装第三方软件了，需要你拥有一个安卓手机，安装小米电视助手才可以。 any mech... https://johnd297agl2.ageeksblog.com/profile