List of Difficult Problems

The current list of difficult questions: (The ones that do not have links are not ready for posting yet.) As noted previously, you may not be able to display the XHTML version unless your browser is up-to-date and you have the math fonts. See page http://www.pdas.com/ralph/mathml.html for help.

• Why doesn't the atmosphere fall to the ground? XHTML, 6KB
• How thick is the earth's atmosphere? XHTML, 6KB
• What is geopotential altitude? XHTML+MathML, 6KB or PDF, 42KB.
• What are the equations of hydrostatic equilibrium? PDF, 50KB
• What is the surface area of a Sears-Haack body? XHTML+MathML, 6KB or PDF, 46KB
• How do you compute the wave angle for a given Mach and deflection angle in an oblique shock? XHTML+MathML, 5KB or PDF, 42 KB
• How do you compute the trajectory of a baseball in air? XHTML, 8KB
• How do you compute the inverse of the Prandtl-Meyer function? XHTML+MathML, 5KB or PDF, 44KB
• What is the difference between a Sears-Haack body and a Von Karman Ogive?
• What is the wave drag coefficient of a body of revolution defined by the radius at a finite set of points?
• What is the supersonic area rule?
• What is the induced drag coefficient of a wing whose local lift coefficient is known at a finite set of points?
• How does one compute the shape of a NACA 6-series airfoil?
• What is Shock-Expansion Theory?
• What is Second-Order Shock-Expansion Theory?