line+of+motion
131Proper motion — The proper motion of a star is its angular change in position over time as seen from the center of mass of the solar system.[1] It is measured in seconds of arc per year, arcsec/yr, where 3600 arcseconds equal one degree.[2] This contrasts with… …
132laws of motion — plural noun see under ↑motion • • • Main Entry: ↑law laws of motion 1. Newton s three laws: (1) every body continues in its state of rest, or of uniform motion in a straight line, except so far as it may be compelled by force to change that state …
