Suppose you purchase a 4x8 piece of plywood from home depot. you don't have a pickup truck (nor does your friend), but you do have a roof rack with cross bars on your car. so you will have to secure the plywood to the roof rack in order to get it home. your friend (the one who does not have a pickup truck) suggests that you tie the plywood on sideways (so that the short edge is front to back) and drive at about 13 mph. use standard sea-level conditions p=0.002369 slugs/ft3 and 1 = 3.7372 x 10-7 slugs/ft-s.
(a) estimate the drag on the plywood for the case suggested by your friend.
(b) estimate the drag on the plywood if you turn the sheet so that the long edge is front to back.
(c) explain why your friend suggested the sideways configuration.