Small telescopes are often advertised as " 200 power" or "magnifies 200 times." How would you change these advertisements to market to astronomers?
What will be an ideal response?
One should state the diameter of the primary lens or mirror and the optical quality.
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In space-based systems, such as the International Space Station, for example, highly efficient cooling systems are deployed that involve force convection boiling. In a laboratory experiment to develop one such system, a test liquid, which has the physical properties given, flows inside a vertical tube of 1.905 cm (or 0.75 in) inner diameter with a mass flux (or mass velocity) of 680 kg/(m2s). Determine the heat transfer coefficient at a point along the length of the tube at which the quality is 0.3. The wall temperature at this location was measured to be 1800C.
GIVEN
? 1.905 cm vertical tube with flowing, boiling water inside
? Test liquid with properties given above
? Mass flux (G)= 680 kg/(m2s)
FIND
(a) Heat transfer coefficient at a point along the length of the tube at which the quality is 0.3
ASSUMPTIONS
? The method of Chen is applicable
? Prandtl number of the fluid is Prl=1.0
PROPERTIES AND CONSTANTS
In 1975 the roof of Montreal's Velodrome, with a weight of 360 kN, was lifted by 10 cm so that it could be centered. How much work was done on the roof by the forces making the lift? In 1960 Mrs. Maxwell Rogers of Tampa, Florida, reportedly raised one end of a car that had fallen onto her son when a jack failed. If her panic lift effectively raised 4000 N (about 1/4 of the car's weight) by 5.0 cm, how much work did her force do on the car?
What will be an ideal response?
What is the most likely origin of the Valles Marineris on Mars?
A) it is a fissure in the surface carved out by a giant impact B) it is a tectonic fracture associated with the formation of the adjacent Tharsis bulge C) it is a huge canyon system formed by water erosion D) it was formed from the separation of two tectonic plates
A carbon resistor has a resistance of 18 ? at a temperature of 20°C. What is its resistance at a temperature of 120°C? (The temperature coefficient of resistivity for carbon is -5.0 × 10-4 /C°.)
A) 18 ? B) 17 ? C) 16 ? D) 15 ? E) 14 ?