Planet X-39 has a mass equal to 1/3 that of Earth and a radius equal to 1/3 that of Earth. If V is the escape speed for Earth, what is the escape speed for X-39?
A) V
B) 3V
C) 6V
D) V/9
E) 9V
A
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The test data tabulated on the next page were reduced from measurements made to determine the heat-transfer coefficient inside tubes at Reynolds numbers only slightly above transition and at relatively high Prandtl numbers (as associated with oils). Tests were made in a double-tube exchanger with a counterflow of water to provide the cooling. The pipe used to carry the oils was 1.5 cm-OD, 18 BWG, 3 m-long. Correlate the data in terms of appropriate dimensionless parameters.
Hint: Start by correlating Nu and ReD irrespective of the Prandtl numbers, since the influence of
the Prandtl number on the Nusselt number is expected to be relatively small. By plotting Nu vs.
Re on log-log paper, one can guess the nature of the correlation equation, Nu = f1 (Re). A plot of
Nu/f1 (Re) vs. Pr then reveals the dependence upon Pr. For the final equation, the influence of
the viscosity variation also is considered.
GIVEN
Oil in a counterflow heat exchanger
Pipe specifications: 1.5 cm-OD, 18 BWG
Pipe length (L) = 3 m
The experimental data above
FIND
Correlate the data in terms of appropriate dimensionless parameters
ASSUMPTIONS
The data represents the steady state for each case
PROPERTIES AND CONSTANTS
From Appendix 2, Table 42: for 1.5 cm OD, 18 BWG tubing, the inside diameter D = 1.338 cm
LCD stands for:
a. linearly collimated diffraction. b. longitudinally combined depolarization. c. liquid crystal display. d. lighted compact disk.
A solenoid 4.0 cm in radius and 4.0 m in length has 8000 uniformly spaced turns and carries a current of 5.0 A. Consider a plane circular surface (radius = 2.0 cm) located at the center of the solenoid with its axis coincident with the axis of the solenoid. What is the magnetic flux through this surface? (1 Wb = 1 T / m2)
a. 63 ?Wb b. 16 ?Wb c. 0.25 mWb d. 10 ?Wb e. 5.0 ?Wb
A tractor T is pulling two trailers, 
and 
with a constant acceleration. T has a mass of 200 kg, 
has a mass of 100 kg, and 
has a mass of 150 kg. If the forward acceleration is 0.60 
then the horizontal force on the tractor due to the ground is
A. 270 N backward.
B. 270 N forward.
C. 150 N backward.
D. 150 N forward.
E. 90 N forward.