Radioactivity Basics: Rubidium 
Rb is a naturally occurring isotope that undergoes ?- decay. What isotope is the product of this decay?
A. 
Kr
B. 
Kr
C. 
Rb
D. 
Sr
E. 
Sr
Answer: E
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Calculate the water side heat transfer coefficient and the coolant pressure drop per unit length of tube for the core of a compact air-to-water intercooler for a 3.7 MW gas turbine plant. The water flows inside of a flattened aluminum tube having the cross- section shown belowThe inside diameter of the tube before it was flattened was 1.23 cm with a wall thickness (t) of 0.025 cm. The water enters the tube at 15.6°C and leaves at 26.7°C at a velocity of 1.34 m/s.
GIVEN
Water flow in a flattened tube as shown above
Inlet temperature (Ti) = 15.6°C
Outlet temperature (To) = 26.7°C
Water velocity (V) = 1.34 m/s
FIND
(a) The heat transfer coefficient on the inside of the tubes hc
(b) The pressure drop per unit length (?p/L)
ASSUMPTIONS
Steady state
Fully developed flow
PROPERTIES AND CONSTANTS
From Appendix 2, Table 13, for water at the average temperature of 21.1°C
Light entering a transparent material from the air:
a. bends toward the normal. b. bends away from the normal. c. bends toward its source. d. does not bend. e. is entirely reflected.
The basic physical principal principle that explains the operation of rocket engines is
A) the atomic hypothesis. B) the law of force pairs. C) Galileo's principle of falling. D) the law of inertia. E) Actually, rockets are unexplainable.
Elements heavier than hydrogen and helium constitute about ________ of the mass of the Milky Way's interstellar medium.
A) 0.002 % B) 2 % C) 70 % D) 98%