Why is rolling a ball down a hill considered an unbalanced force?

hello

Explanation:

A ball starts from rest and rolls down a hill with uniform acceleration, traveling 170 m during the second 5.5 s of its motion. How far did it roll during the first 5.5 s of motion? Express your answer using two significant . physics.

hope its right

it will eventually stop because of friction

the answer is lactic acid from anaerobic respiration. the acid in lactic acid is what creates sore and burning muscles. if you think about how acid burns that will give you a clue for questions like this.