An astronaut is in equilibrium when he is positioned from the center of asteroid X and from the center of asteroid Y, along the straight line joining the centers of the asteroids. What is the ratio of the masses X/Y of the asteroids?
A) 0.0581
B) 17.2
C) 0.241
D) 4.15
Answer: A
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A(n) _________is a device that allows the angle of a sample relative to a reference to be changed and measured.
Fill in the blank(s) with the appropriate word(s).
Carbon dioxide gas at 1 atmosphere pressure it to be heated from 25°C to 75°C by pumping it through a tube bank at a velocity of 4 m/s. The tubes are heated by steam condensing within them at 200°C. The tubes have 10 mm OD, are in an in–line arrangement, have a longitudinal spacing of 15 mm and a transverse spacing of 17 mm. If 13 tube rows are required, what is the average heat transfer coefficient and what is the pressure drop of the carbon dioxide?
GIVEN
• In-line tube bank: condensing steam inside, CO2 outside
• CO2 temperatures
? In: (Tg,in) = 25°C
? Out: (Tg,out) = 75°C
• CO2 velocity (Us) = 4 m/s
• Steam temperature (Ts) = 200°C
• Tube outside diameter (D) = 10 mm = 0.01 m
• Longitudinal spacing (SL) = 15 mm = 0.015 m
• Transverse spacing (ST) = 17 mm = 0.017 m
• Number of tubes (N) = 13
FIND (a) The average heat transfer coefficient (hc) (b) The CO2 pressure drop (?p)
ASSUMPTIONS
• Steady state
• The thermal resistances of the condensing steam and the tube walls are negligible (tube wall temperature = Ts)
SKETCH
Potassium-40 decays to argon-40 has a half-life of 1.25 billion years. Suppose you find a rock that has only 1/8 of its original potassium-40 still remaining. How old is the rock?
A) 3.75 billion years B) 5.25 billion years C) 2.5 billion years D) 1.25 billion years E) 4.5 billion years
The statement "No detectable change in the total mass occurs during a chemical reaction" is known as the law of ______________
Fill in the blank(s) with correct word