On the scale of the cosmic calendar, in which the history of the universe is compressed into 1 year, when did the dinosaurs become extinct?
A) in late December
B) in late November
C) in late October
D) in late September
E) in late August
A) in late December
You might also like to view...
Our solar system contains more than 100 Kuiper Belt objects larger than 300 km in diameter
Indicate whether the statement is true or false
A 5,000 kg satellite is orbiting the Earth in a circular path. The height of the satellite above the surface of the Earth is 800 km. The velocity of the satellite is 
A. 7,460 m/s. B. 6,830 m/s. C. 6,430 m/s. D. 5,950 m/s. E. 5,350 m/s.
A black sphere (2.5-cm in diameter) is placed in a large infrared heating oven whose walls are maintained at 370°C. The temperature of the air in the oven is 90°C and the heat-transfer coefficient for convection between the surface of the sphere and the air is 30 W/(m2 K). Estimate the net rate of heat flow to the sphere when its surface temperature is 35°C.
GIVEN
• A black sphere in a large infrared heating oven
• Sphere diameter (D) = 2.5 cm = 0.025 m
• Oven wall temperature (T2) = 370°C = 643 K
• Oven air temperature (T?) = 90°C = 363 K
• Convective heat transfer coefficient (hc) = 30 W/(m2 K)
• Sphere surface temperature (T1) = 35°C = 308 K
FIND
• The net rate of heat flow to the sphere (qtotal)
ASSUMPTIONS
• The oven walls are diffuse
SKETCH
PROPERTIES AND CONSTANTS
the Stephan-Boltzmann constant (?) = 5.67 × 10–8 W/m2K4
Earth's magnetic field is generated by the dynamo effect in the
a. molten metallic core. b. solid central core. c. plastic mantle. d. crust. e. aurora.