the Explorer 32 satellite was able to determine the density of the upper atmosphere through ground-based observations of the effect of drag on the satellite?

Question 1: The notion of ________ — introduced by Prandtl in 1904, founded on both theory and experiments — explained the causes of drag at high Reynolds numbers.

Question 2: In ________, and depending on the situation, atmospheric drag can be regarded as an inefficiency requiring expense of additional energy during launch of the space object or as a bonus simplifying return from orbit.

Question 6: In 1752 d'Alembert proved that ________, the 18^{th} century state-of-the-art inviscid flow theory amenable to mathematical solutions, resulted in the prediction of zero drag.

Question 7: The standard equation for drag is one half the coefficient of drag multiplied by the fluid mass density, the ________ of the specified item, and the square of the velocity.

Question 8: The velocity as a function of time for an object falling through a non-dense medium, and released at zero relative-velocity v = 0 at time t = 0, is roughly given by a function involving a ________ (tanh):

Question 9: For a solid object moving through a fluid, the drag is the component of the netaerodynamic or hydrodynamic________ acting opposite to the direction of the movement.