出典:Wikipedia
出典:『Wikipedia』 (2011/07/13 04:55 UTC 版)
In physics, velocity is the measurement of the rate and direction of change in the position of an object. It is a vector physical quantity; both magnitude and direction are required to define it. The scalar absolute value (magnitude) of velocity is speed, a quantity that is measured in metres per second (m/s or ms−1) when using the SI (metric) system.