A white dwarf whose red giant companion dumps hydrogen onto it may
a. show no effect.
b. explode recurrently as a nova.
c. blow up as a type I supernova.
d. explode recurrently as a nova or blow up as a type Ia supernova.
d
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When the Sun moves off the main sequence, it will next become a(n) ______________
Fill in the blank(s) with correct word
You live at a latitude of 39° S. What is the angle between the southern horizon and the south celestial pole?
a. 45° b. 23.4° c. 39° d. 51° e. The answer depends on the day of the year.
The semimajor axis of an ellipse is
a. the ratio of the longest diameter of the ellipse to that of the shortest diameter of the ellipse. b. half the length of the shortest diameter of the ellipse. c. half the length of the longest diameter of the ellipse. d. the distance between the two foci of the ellipse. e. the ratio of the distance between the two foci to the length of half the longest diameter of the ellipse.
Water at an average temperature of 27°C is flowing through a smooth 5.08-cm-ID pipe at a velocity of 0.91 m/s. If the temperature at the inner surface of the pipe is 49°C, determine (a) the heat transfer coefficient, (b) the rate of heat flow per meter of pipe, (c) the bulk temperature rise per meter, and (d) the pressure drop per meter.
GIVEN
• Water flowing through a smooth pipe
• Average water temperature (Tw) = 27°C
• Pipe inside diameter (D) = 5.08 cm = 0.0508 m
• Water velocity (V) = 0.91 m/s
• Inner surface temperature of pipe (Ts) = 49°C FIND
(a) The heat transfer coefficient ( h c)
(b) The rate of heat flow per meter of pipe (q/L)
(c) The bulk temperature rise per meter of pipe (?Tw/L)
(d) The pressure drop per meter of pipe (?p/L)
ASSUMPTIONS
• Steady state
• Fully developed flow
SKETCH
PROPERTIES AND CONSTANTS
for water at 27°C
Density (?) = 996.5 kg/m3
Specific Heat (cp) = 4178 J/(kg K)
Thermal conductivity (k) = 0.608 W/(m K)
Absolute viscosity (?) = 845.3 × 10–6 (Ns)/m2
Kinematic viscosity (?) = 0.852 × 10–6 m2/s
Prandtl number (Pr) = 5.8 At the surface temperature of 49°C
Absolute viscosity (?s) = 565.1 × 10–6 (Ns)/m2