Step-by-step explanation:
The velocity of an object is given by the rate of change of position as :

where
is the rate of change of velocity
From the position time graph of an object, the velocity of an object can be calculated using the slope of the graph. From the attached figure it is clear that the velocity is given by :


m = 10
i.e.
Velocity, v = 10 m/s
Hence, to calculate the velocity of an object the slope of the position vs time graph should be calculated