7. The European Space Agency launched a probe called Rosetta in March 2004. In August 2014, Rosetta reached its destination: a comet called 67P/Churyumov-
Gerasimenko. Rosetta is the first spacecraft to rendezvous with a comet. It contained a
lander craft, called Philae.
The Rosetta has a launch mass on Earth of 3000 kilograms [kg] and the Philae
has a launch mass of 220 pound-mass (lb). In order to escape Earth's gravity,
the combined spacecraft must accelerate at a rate of 25,000 miles per hour
squared (mi/h²]. How much thrust, in units of newtons [N], must the engines
provide to reach this acceleration?

Air is to be cooled in the evaporator section of a refrigerator by passing it over a bank of 0.8-cm-outer-diameter and 0.4-m-long tubes inside which the refrigerant is evaporating at -20°c. air approaches the tube bank in the normal direction at 0°c and 1 atm with a mean velocity of 4 m/s. the tubes are arranged in-line with longitudinal and transverse pitches of sl- st 1.5 cm. there are 30 rows in the flow direction with 15 tubes in each row. determine (a) the refrigeration capacity of this system and (b) pressure drop across the tube bank. evaluate the air properties at an assumed mean temperature of -5°c and 1 atm. is this a good assumption?

The flow rate of air through a through a pipe is 0.02 m5/s. a pitot static tube is placed in the flow. the radius of the pitot static tube is 1 mm. assuming the flow to be steady and the air to be at 300k, calculate the difference in total and static pressure if the diameter of the pipe is: (a) d 0.1 m d 0.05 m (c) d 0.01 m

Aturning operation is performed with following conditions: rake angle of 12°, a feed of 0.35 mm/rev, and a depth of cut of 1.1 mm. the work piece is aluminum alloy 6061 with t6 heat treatment (a16061-t6). the resultant chip thickness was measured to be 1.0 mm. estimate the cutting force, fc. use shear stress of 207 mpa and coefficient of friction on the tool face of 0.6.