1. The problem statement, all variables and given/known data The graph in the figure describes the acceleration as a function of time for a stone rolling down a hill starting from rest. Find the change in the stone's velocity between 2.5s and 7.5s. 2. Relevant equations I think v = v0t +1/2at^2 3. The attempt at a solution I honestly have no idea about how to solve this problem. My professor gives us mastering physics homework problems before he teaches us how to do the material and I'm completely lost right now :/ Any help would be appreciated.