If you looked at the field of view seen in this Hubble Space telescope with your naked eye, about how big would it appear in the sky?
A) about the size of the Big Dipper
B) about the size of the full Moon
C) about the size of your little finger held at arm's length against the sky
D) about the size of this period – . – viewed at arm's length against the sky
D) about the size of this period – . – viewed at arm's length against the sky
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Which of the following is the oldest geological feature of the Moon?
a. maria b. lowlands c. highlands d. regolith e. rilles
First Law of Thermodynamics: A sealed rigitd tank contains 30 moles of an ideal gas, at an initial temperature of 270 K. The pressure of the gas is increased until the final pressure equals 1.40 times the initial pressure. The heat capacity at constant pressure of the gas is 32.0 J/mol ? K. What is the change in the internal (thermal) energy of the gas during this process? (R = 8.31 J/mol ? K)
A. 77 kJ B. 100 kJ C. 130 kJ D. -50 kJ E. -23 kJ
A blood warmer is often used in certain clinical transfusion procedures. While safely storing and preserving blood requires refrigeration, cold blood when used in rapid transfusion procedures could cause clinically dangerous hypothermia in a patient. A new compact and miniature heat exchanger has been proposed that is used “inline” with the transfusion delivery system. It consists of a multi-tube bundle of 5-mm diameter tubes arranged in an equilateral-triangular array with tube centers 7.5 mm apart. Blood flows inside the tubes and is warmed by a heated airstream that is in external cross flow such that the tube surface is maintained at 40°C. The inlet air flow to the tube array is at 70°C with a free stream velocity of 2 m/s, and there are five lateral or transverse rows in the
bundle. Determine the average heat transfer coefficient and pressure drop in the airstream. Also, what is the change in both of these quantities if the tube center-to-center pitch is reduced to 6.0 mm? GIVEN Heated air flowing over an equilateral staggered tube bank Air temperatures Tair,in = 70°C Number of tube rows (N) = 5 Tube diameter (D) = 5 mm= 0.005 m Center to center pitch(S) = 7.5 mm=0.0075 m Free stream velocity (Ua) = 2 m/s Tube surface temperature (Tt) = 40°C FIND The average heat transfer coefficient ( h c) and pressure drop in airstream. Change in average heat transfer coefficient and pressure drop when center to center pitch is reduced to 6 mm. ASSUMPTIONS Steady state The correlation of Equation 6.38 can be applied to a pitch-to-diameter ratio of 1.5 Tube wall temperature is uniform and constant
Why are several observations or trials taken for each measurement?