What will be the ratio of distances moved by a freely falling body from rest in 4^th and 5^th seconds of journey

Given figure shows velocity-time graph of a ball of mass 250g rolling on a concretefloor. Compute the acceleration and the frictional force of the floor on the ball?

What will be the ratio of distances moved by a freely falling body from rest in 4^th and 5^th seconds of journey