posted by Sandhya .
A skydiver is falling straight down at 60 m/s when he opens his parachute and slows to 8.3 m/s in 4.0 s. What is the average acceleration of the skydiver during those 4.0 s? (Assume that "up" is the positive direction.)
= (velocity change)/(time)
You are given the final and initial velocity. The V change is
8.3 - 60 = -51.7 m/s