Step-by-step explanation:
The velocity vs time graph is used to find the acceleration of an object. The slope of a graph is given by :
![m=(y_2-y_1)/(x_2-x_1)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/fc06wy5n2hf2a0hmyba6df4ibmxk1cn53a.png)
Also, the rate of change of velocity is called the acceleration of an ball.
So, the slope of velocity time graph is used to estimate the acceleration of the ball.