A sky diver of mass 66 kg can slow herself to a constant speed of 99 km/h by orienting her body horizontally, looking straight down with arms and legs extended. In this position, she presents the maximum cross-sectional area and thus maximizes the air-drag force on her.

(a) What is the magnitude of the drag force on the sky diver?

(b) If the drag force is equal to bv2, what is the value of b?

(c) At some instant she quickly flips into a "knife" position, orienting her body vertically with her arms straight down. Suppose this reduces the value of b to 54 percent of the value in Parts (a) and (b). What is her acceleration at the instant she achieves the "knife" position?