Stationary refers to something that is standing still or not moving.
eg. The car is stationary.
Stationery (with an e) is used as a term to describe items related to writing such as pens, paper,...
If you are referring to "Permanent and Stationary," in it's simplest form it means "unchanging." However, this term is used within a variety of areas to include, the medical field, for dictionary...
Yes.
If a crate placed on an inclined plane is moving at constant velocity or not moving at all -- which is really a special case of constant velocity where the velocity is zero -- then the sum of...