The ratio of the distances travelled by a freely falling body in the 1^st, 2^nd, 3^rd and 4^th second

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