Velma, inside a train moving at 20 m/s, throws a rock in the forward direction at 5 m/s. According to her the rock moves at 5 m/s. According to Mort, standing on Earth outside the train, the rock moves at [approximately] 25 m/s. Who is correct?
A) The Wizard of Oz.
B) Velma, because she threw the rock.
C) Mort, because he is standing on Earth.
D) Both, relative to their own reference frames.
E) Neither, because there is no universal "best" reference frame.
D
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A thermocouple (0.8-mm-OD wire) used to measure the temperature of quiescent gas in a furnace gives a reading of 165°C. It is known, however, that the rate of radiant heat flow per meter length from the hotter furnace walls to the thermocouple wire is 1.1 W/m and the convective heat transfer coefficient between the wire and the gas is 6.8 W/(m2K). With this information, estimate the true gas temperature. State your assumptions and indicate the equations used.
GIVEN
• Thermocouple (0.8 mm OD wire) in a furnace
• Thermocouple reading (Tp) = 165°C
• Radiant heat transfer to the wire (qr/L) = 1.1 W/m
• Heat transfer coefficient ( ch ) = 6.8 W/(m2 K)
FIND
• Estimate the true gas temperature (TG)
ASSUMPTIONS
• The system is in equilibrium
• Conduction along the thermocouple is negligible
• Conduction between the thermocouple and the furnace wall is negligible
SKETCH
The relationship between the rotation of Mercury and its revolution is referred as a(n) _______________
Fill in the blank(s) with correct word
The Very Long Baseline Array (VLBA)
a. is the highest resolution optical telescope ever built. b. is located in Arecibo, Puerto Rico. c. is a matched pair of 8 m telescopes, one of which is in Chile and the other in Hawaii. d. is an air-borne infrared telescope. e. is a set of radio telescopes linked together electronically to provide very high resolution.