The size and shape of a planet's orbit can be determined by
A) the Doppler technique.
B) transit observations.
C) spectral measurements.
D) knowing the planet's mass by any technique and applying Newton's version of Kepler's third law.
E) gravitational microlensing.
A
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A mercury-in-glass thermometer at 40°C (OD = 1 cm) is inserted through duct wall into a 3 m/s air stream at 66°C. This can be modelled as cylinder in cross-flow, as shown in figure. Estimate the heat transfer coefficient between the air and the thermometer.
GIVEN
• Thermometer in an air stream
• Thermometer temperature (Ts) = 40°C
• Thermometer outside diameter (D) = 1 cm = 0.01 m
• Air velocity (V) = 3 m/s
• Air temperature (Tb) = 66°C
FIND
• The heat transfer coefficient ch
ASSUMPTIONS
• Steady state
• Turbulence in the free stream approaching the thermometer is low
• Effect of the duct walls in negligible
SKETCH
PROPERTIES AND CONSTANTS
From Appendix 2, Table 28, for dry air at the bulk temperature of 66°C
Thermal conductivity (k) = 0.0282 W/(m K) Kinematic viscosity (?) = 20*10-6 m2/s Prandtl number (Pr) = 0.71 At the thermometer surface temperature of 40°C, the Prandtl number (Prs) = 0.71
A series LR circuit consists of a 2.0-H inductor with negligible internal resistance, a 100-ohm resistor, an open switch, and a 9.0-V ideal power source. After the switch is closed, what is the maximum power delivered by the power supply?
A) 8.1 W B) 0.090 W C) 0.81 W D) 81 W E) 0.40 W
Determine the activation enthalpy for creep in titania at a stress of 41 MPa
From the Earth, they see the Enterprise approaching at 0.800c and the Klingons approaching from the opposite direction at 0.900c. From the Enterprise, the crew sees the Klingon ship approaching at what speed?
What will be an ideal response?