1. The problem statement, all variables and given/known data 2. Relevant equations 3. The attempt at a solution I know velocity = distance/time and the steepest gradient means the maximum speed, and the gradient is steepest between 1 and 1.5 seconds with the change in distance being around 40cm so velocity = 40cm/0.5 = 80 cm per second. So my answers are nowhere near what they want. Where am I going wrong?