(a) a box with its contents has a total mass of 20 kg. it is dropped from a very high building. after reaching terminal speed, what is the magnitude of the air resistance force acting upward on the falling box? n (b) the box survived the fall and is returned to the top of the building. more objects are put into the box, and the box with its contents now has a total mass of 65 kg. the box is dropped, and it reaches a higher terminal speed than before. after reaching terminal speed, what is the magnitude of the air resistance force acting upward on the falling box? (the fact that the heavier object reaches a higher terminal speed shows that the air resistance force increases with increasing speed.)