If the velocity of the object changes from 4 cm / sec to 14 cm / sec in 4 seconds, then at what average rate is the velocity changing?

It  requires 5 seconds, starting from rest, for a ball to roll the 71 centimeter length of a uniform incline.

An object which accelerates uniformly from rest will attain a final velocity which is double its average velocity.

At what average rate does the velocity of an airplane change, if it accelerates uniformly down a runway, starting from rest, requiring 8 seconds to cover a distance of 175 meters.