A Person Pushes Horizontally on a Heavy Box and Slides

Multiple Choice

A person pushes horizontally on a heavy box and slides it across the level floor at constant velocity. The person pushes with a 60.0 N force for the first 6.88 m, at which time he begins to tire. The force he exerts then starts to decrease linearly from 60.0 N to 0.00 N across the remaining 6.88 m. How much total work did the person do on the box?

A) 619 J
B) 826 J
C) 495 J
D) 925 J