Which example best demonstrates how unbalanced forces change the speed of an object's motion? a) a child on a bicycle braking at a stop sign. b) a child singing a song. c) a child sitting in a chair reading a book. d) a child walking around the corner of a school hallway.

A) A child on a bicycle braking at a stop sign.

Explanation:

The child is applying the brakes to dramatically slow down the movement of his body, which couldn't be done without the bike. The bike is acting the same as a car would to us, it propels us and is capable of slowing down or stopping our motion whenever we need.

force tends to be low and long diustance masses are high

we're given that v₀ = 0 and a = 5.4 m/s². therefore, since v = at + v₀ for constant acceleration the equation for velocity is

after 28s,

m/s

which i would round to 150 m/s as my final answer