To calculate the velocity on an object, the of the position vs time graph should be calculated

Slope of graph

Explanation:

The total displacement divided by total time taken by an object is called its velocity. When a position - time (x-t) graph is plotted, the magnitude of velocity is given by its slope.

The slope of position-time graph gives the velocity of an object. The attached figure shows a position time graph.

The slope of this graph is given by :

i.e.

The velocity of this object is 10 m/s. So, to calculate the velocity on an object, the slope of the position vs time graph should be calculated.                              

friedrich meischer discovered it in white blood cell