7. A ball is thrown with an initial velocity V at an angle θ above the horizontal. Which of the graphs below best represents the relationship between the ball’s horizontal speed as it moves toward its maximum height and time? [Neglect friction]

The ratio of lift to drag l/d for a wing or airfoil is an important aerodynamic parameter, indeed, it is a direct measure of the aerodynamic efficiency of the wing. if a wing is pitched through a range of angle of attack, l/d first increases, then goes through a maximum, and then decreases. consider an infinite wing with an naca 2412 airfoil. estimate the maximum value of l/d. assume that the reynolds number is 9x10^6.