Apply the grid method to each situation that follows.

a. Use Eq. (11.17) to predict the lift force in newtons for a spinning baseball. Use a coefficient of lift of C_L = 1.2. The speed of the baseball is 90 mph. Calculate area using A = πr², where the radius of a baseball is r = 1.45 in. Assume a hot summer day. 

b. Use Eq. (11.17) to predict the size of wing in mm² needed for a model aircraft that has a mass of 570 g. Wing size is specified by giving the wing area (A) as viewed by an observer looking down on the wing. Assume the airplane is traveling at 80 mph on a hot summer day. Use a coefficient of lift of C_L = 1.2. Assume straight and level flight so lift force balances weight.