How do we express mathematically speed, velocity and acceleration?
If you are kind enough, please answer this too: In what unit do we express speed/velocity in MKS, CGS and FPS?
Although Speed and Velocity may essentially seem to be representing the same thing, it is important not to confuse the two.
Speed is a scalar measurement, in that it only indicates magnitude. It is expressed in units of distance/time. This is obvious when looking at the equation, Speed=Distance/Time. Examples include 30 feet per second, 200 miles per hour etc.
Velocity is a vector measurement, in that it indicates both magnitude and direction. It is expressed in units of displacement/time. This is obvious when looking at the equation, Velocity=Displacement/Time. However it is expressed in the same units as Speed.
(The difference between distance and displacement is that distance represents the total length of ground covered, where as displacement only represents the length from the point of origin. i.e. An athlete running around a 400m track for 1 complete lap has travelled a distance of 400m but a displacement of 0m.)
Acceleration is the rate of change of velocity. It is given by the equation, Acceleration=Velocity/Time and expressed in distance/time squared. Examples include 5 metres per second squared, 20 feet per second squared etc.
IBPH Ep. 3 Speed, Velocity and Acceleration – Part 1 of 3