Indicate whether the statement is true or false. a hypothesis is not scientific if there exists no test for proving it wrong.
a. true
b. false

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.

Which planet do you think would be easiest for humans to colonize some day?

Is the vertical component of velocity ever zero?