Black dwarfs are
A) rare, for collapsing cores of over three solar masses are uncommon.
B) very common, making up the majority of the dark matter in the universe.
C) often made from very low mass protostars that never fuse hydrogen.
D) rare, for few binary systems are close enough for this merger to happen.
E) not found yet; the oldest, coldest white dwarf in the Galaxy has not cooled enough yet.
E
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An intercooler of an air compressor is to use a finned flat tube heat exchanger as shown in Figure 9-29. Compressed air at 100 psia, 130ºF passes through the tubes at 100 ft/s and air at 14.7 psia, 70ºF, and 100 ft/s passes around the tubes. Determine the convective heat transfer coefficient, the friction factor for the cooling air outside the tubes, and the overall convective heat transfer coefficient for the intercooler. Assume the inside dimensions of the flattened tubes are 0.105 in by 0.865 in.
Given that 1.00 in. = 2.54 cm, how many square centimeters are in 1.00 square inch?
A) 1.59 B) 2.54 C) 5.08 D) 6.45
Although some photographs show what looks like jets of material near many young stars, we now know that these "jets" actually represent gas from the surrounding nebula that is falling onto the stars
Indicate whether the statement is true or false
A block is on a frictionless table, on earth. The block accelerates at 5.3 m/ when a horizontal force is applied to it. The block and table are set up on the Moon where the acceleration due to gravity is 1.62 m/
A horizontal force of 5 N is now applied to the block when it is on the Moon. The acceleration imparted to the block by this force is closest to A) 2.7 m/ . B) 2.4 m/ . C) 2.9 m/ . D) 3.2 m/ . E) 3.4 m/ .