In [[physics]], speed refers to the magnitude of the [[velocity]] of an object.
+
In [[physics]],
+
'''speed''' refers to the magnitude of the [[velocity]] of an object.
−
'''Speed''' is the total [[distance]] traveled divided by the [[time]] it takes to travel it<ref>Serway and Beichner, ''Physics for Scientists and Engineers'', Fifth Edition</ref>.
+
Speed is the total [[distance]] traveled divided by the [[time]] it takes to travel it.<ref>Serway and Beichner, ''Physics for Scientists and Engineers'', Fifth Edition</ref>
<math>Speed=\frac{d D}{d t}</math>
<math>Speed=\frac{d D}{d t}</math>
−
Note that speed is a [[scalar]], therefore it has no direction or sign.
+
Note that speed is a [[scalar]], therefore it has no direction, and because it is a measure of magnitude, it is never negative.
−
Like velocity, units for its measurement are [[meter]]/[[second]] and more commonly in informal circumstances [[kilometer]]/[[hour]] and [[mile]]/[[hour]].
+
Like velocity, units for its measurement are [[meter]]s/[[second]] (m/s), and more commonly in informal circumstances [[kilometer]]s/[[hour]] (kph) or (km/h) and [[mile]]s/[[hour]] (mph) or (MPH).