What is the upper block's acceleration if the coefficient of kinetic friction between the block and the table is 0.13?

The force pulling the block forward will be equal to the weight of the hanging box.
F = mg = g

The resistance will be equal to μR, where R is the reaction force and μ is the coefficient of friction. 

Resultant force = g - μmg
ma = g - μmg
a = g(1 - 2μ) / 2
a = 3.63 m/s²

As newton's first law states a object in motion stays in motion

The purpose of a lab is to do your "expirements" the importance of the topic is so you can now what the story is about and the last one is because no one is me with my question ( what is 3 over 4 x - 9 = 27 maybe you can )