Lew walks every day at lunch when he is working. The amazing thing about Lew is that he walks at a constant rate (velocity) the entire time he walks. He walks for $1$ hour every day and travels at a rate of $4$ miles per hour.  

1. Sketch a velocity graph of Lew’s lunchtime walk, being sure to label both axes. Shade the area between the curve and the $x$-axis over the appropriate domain.

2. What are the domain and the range of this function?

3. The region that is shaded on your graph should resemble a rectangle. What are the units when calculating the area of the shaded region? Use unit analysis to justify your answer.

4. What is the area of the shaded region? Include the proper units.