But if you calculate the acceleration without the graph, you are explicitly stating that the y-intercept is zero---which it might not be. So there are some actual reasons for making a graph.

Let's start by calculating the angle for a runner with an acceleration of 9.8 m/s 2. In this case, what would the lean angle be at? ... From this, I get the following position-time graph ...

Learn the uses of equations and graphs of motion and how to determine other aspects of the motion of objects. BBC Bitesize Scotland Higher Physics revision.

Remember, acceleration is the same as gradient, and acceleration = velocity change ÷ time. Look at the graph. The acceleration of the vehicle in the first 10 seconds is: ...