Why is Polaris not always the pole star, and when does it get another chance?
What will be an ideal response?
Precession of the Earth's axis of rotation takes around 26,000 years.
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Which has the greater specific heat capacity; the filling of a hot piece of pie or the crust?
A) the filling B) the crust C) depends on the temperature
A long wire 0.7 mm in diameter with an emissivity of 0.9 is placed in a large quiescent air space at 270 K. If the wire is at 800 K, calculate the net rate of heat loss. Discuss your assumptions.
GIVEN
• Long wire in still air
• Wire diameter (D) = 0.7 mm= 7*10-4 m
• Wire temperature (Ts) = 800 K
• Emissivity (?) = 0.9
• Air temperature (T?) = 270 K FIND
• The net rate of heat loss
ASSUMPTIONS
• The enclosure around the wire behaves as a blackbody enclosure at the temperature of the air
• The natural convection heat transfer coefficient is 18 W/(m2 K)
• Steady state conditions prevail
SKETCH
The origin of any microtides in the human body is most likely the
A) Sun. B) Moon. C) Earth.
A key clue to how the solar system formed is the observation that all the planets orbit close to the same plane
Indicate whether the statement is true or false