Extrasolar planets are placed in groups by their approximate masses. What are four of these classes?
What will be an ideal response?
Planets above about 2 times the mass of Neptune are Jupiters. Planets less massive than this, down to about half the mass of Neptune are Neptunes. Super-Earths are less massive than Neptunes down to about twice the mass of Earth. Earths are planets less massive than that.
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Saturn's larger satellites have lower average density than the Galilean satellites of Jupiter; therefore, we can conclude that Saturn's satellites contain less rock and more ice than the Galilean satellites.
Answer the following statement true (T) or false (F)
The primary scientific purpose of a particle accelerator is to
A) make small particles achieve large accelerations. B) produce energy for commercial use. C) create particles and study their behavior. D) make small particles go very fast.
In a shell of a shell and tube heat exchanger with two shell passes and eight tube passes, 12.6 kg/s of water is heated in the shell from 800C to 150°C. Hot exhaust gases having roughly the same physical properties as air enter the tubes at 340°C and leave at 180°C. The total surface, based on the outer tube surface, is 930 m2 . Determine (a) the log-mean temperature difference if the heat exchanger were simple counterflow type, (b) the correction factor F for the actual arrangement, (c) the effectiveness of the heat exchanger, (d) the average overall heat transfer coefficient.
GIVEN
• A tubular heat exchanger with 2 shell passes and 8 tube passes
• Water in the shell, exhaust gases in the tubes
• Exhaust gases have roughly the same physical properties as air
• Water flow rate m w= 12.6 kg/s
• Water temperatures
? Tw,in = 80°C
? Tw,out = 150°C
• Exhaust temperatures
? Te,in = 340°C
? Te,out = 180°C
• Surface are (A) = 930 m2
FIND
(a) LMTD if the exchanger is a simple counterflow type
(b) Correction F for the actual arrangement
(c) Effectiveness (e)
(d) The overall heat transfer coefficient (U)
SKETCH
PROPERTIES AND CONSTANTS
the specific heat of water at the mean temperature of 130°C (cpw) = 4244.5 W/(kg K)
Consider a uniform horizontal electric field of 50 N/C directed toward the east. If the electric potential measured at a given point is 80 V, what is the potential at a point 1.0 m directly west of that point?
A) 30 V B) 50 V C) 80 V D) 130 V