Speed is distance travelled in a certain time. We are used to dealing with speeds in everyday life we measure the rate at which we travel down the road in our cars in miles (or kilometers) per hour. The distance travelled when measuring speed is cumulative, in other words if we drive 50 miles to a nearby town and return we have travelled a total of 100 miles. Distance travelled should not be confused with displacement which is the distance from an abitary point of origin, so in our previous example we have returned home so our displacement from home is 0 miles.
Speed is a scalar quantity.
Mathematically
Speed
s = d / t
s
speed [m s-1]
d
distance [m]
t
time [s]
Example Content
Dimensions
Speed has dimension of m s-1.
Speed is commonly measured in units of miles per hour, kilometers per hour or in aviation nautical miles per hour or knots [kts].
