A person is walking down the street maintain the same speed and direction. The person is accelerating.

no change in speed, therefore the body cannot be accelerated.  a=0

Explanation:

When a person is accelerating his speed must change, if the speed is in the same direction as the acceleration the speed increases and if the acceleration is in the opposite direction to the speed it decreases.

In this case there is no change in speed, therefore the body cannot be accelerated.

which piece of furniture will have the most inertia and give the furniture movers the most difficulty in moving?  

answer

a 75kg dining table

reserve is the answer