Design and testing of these physical systems rely on standard design practices that employ the laws of conservation of force, mass, and energy.
这些物理系统的测试依赖于对作用力、质量和能量守恒定律的标准设计实践。
A discussion is made of the work done by static frictional force and the conservation of mechanical energy in the work doing process by way of typical cases.
本文就静摩擦力做功以及在静摩擦力做功过程中机械能守恒问题，结合实例做进一步讨论。
Have carried on research to electromagnetic force according to the law of conservation of energy.
依据能量守恒定律对电磁推力进行了研究。
应用推荐