1，打钩use Gravity物体会有重力的效果。
Use GravityIf enabled, the object is affected by gravity.
2，Is Kinematic打勾则把物体放在什么地方，它就是什么地方。
如果Is Kinematic不勾选，物体如果加了box collider，而物体间的box collider相互碰撞，运行时物体会以相碰后的速度运动。
Is KinematicIf enabled, the object will not be driven by the physics engine, and can only be manipulated by its Transform. This is useful for moving platforms or if you want to animate a Rigidbody that has a HingeJoint attached.
