What factors are important when trying to classify a spiral galaxy?
a. Amount of dust and gas in the galaxy
b. Structure of the spiral arms
c. Size of the central region
d. All of the above
D
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You are asked to produce a part that will be shaped by forging from a thick block of metal. Forging is a form of controlled hammering the part into shape that is covered in Section 13.2.1. The final part will have some thin sections that will experience extensive deformation and some thick sections that will experience minimal deformation. It is desired that the mechanical properties of the as forged metal be relatively uniform throughout the part. It is planned to use the part in the as forged condition without subsequent treatment. What defect property of metals may be important in the metal selection, and why is this property important for this design?
What will be an ideal response?
Suppose you have a heat source that gives off a bright white light. Then you lower the temperature. What happens to the light?
The Sun's elliptical shape at sunset can be adequately explained by
A) Fermat's principle. B) the law of refraction. C) both of these D) neither of these
The pressure drop in a tube carrying a viscous fluid is described by
A) Bernoulli's principle. B) Pascal's principle. C) Archimedes' principle. D) Poiseuille's equation. E) Newton's Second law.