The temperature of a flowing gas is to be measured with a thermocouple junction and wire stretched between two legs of a sting, a wind tunnel test fixture. the junction is formed by butt-welding two wires of different material, as shown in the schematic. for wires of diameter 525 μm and a convection coefficient of 700 w/m2·k, determine the minimum separation distance between the two legs of the sting, , to ensure that the sting temperature does not influence the junction temperature and, in turn, invalidate the gas temperature measurement. consider two different types of thermocouple junctions consisting of (a) copper and constantan wires and (b) chromel and alumel wires. evaluate the thermal conductivity of copper and constantan at 300 k. use 19 w/m·k and 29 w/m·k for the thermal conductivities of the chromel and alumel wires, respectively.

Your starship, the aimless wanderer, lands on the mysterious planet mongo. as chief scientist-engineer, you make the following measurements: a 2.50-kg stone thrown upward from the ground at 14.0 m/s returns to the ground in 5.70 s ; the circumference of mongo at the equator is 2.20×10^5 km ; and there is no appreciable atmosphere on mongo. (a) the starship commander, captain confusion, asks for the following information: what is the mass of mongo? (b) if the aimless wanderer goes into a circular orbit 2.20×10^4 km above the surface of mongo, how many hours will it take the ship to complete one orbit? (c) an unmanned spacecraft is in a circular orbit around the moon, observing the lunar surface from an altitude of 44.0 km . to the dismay of scientists on earth, an electrical fault causes an on-board thruster to fire, decreasing the speed of the spacecraft by 23.0 m/s . if nothing is done to correct its orbit, with what speed (in km/h) will the spacecraft crash into the lunar surface?