If the insolation upon a flat plate collector is 800 Btu/ft2/day, how large must the collector be to provide 30,000 Btu/hr of thermal energy for an entire day? Take the efficiency of the collector to be 50%
a. 150 b. 750 c. 1800 d. 4000 e. 7200 ft2
c
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The uncharged particle inside an atom is the
a. electron b. proton c. neutron d. nucleus e. none of the above
Which of the following materials is most appropriate for a design requiring a material with a high magnetic susceptibility that will be subjected to an alternating magnetic field of 60 Hz?
(a) Fe-3 wt. % Si (b) MnO (c) Alnico-5 (d) Fe3O4
Multiple-Object Accelerating Systems: In the figure, block A has a mass of 3.00 kg. It rests on a smooth horizontal table and is connected by a very light horizontal string over an ideal pulley to block B, which has a mass of 2.00 kg. When block B is gently released from rest, how long does it take block B to travel 80.0 cm?
A. 0.404 s B. 0.494 s C. 0.639 s D. 0.785 s E. 0.935 s
What current must be maintained in a square loop (50 cm on a side) to create a torque of 1.0 N / m about an axis through its center and parallel to one of its sides when a magnetic field of magnitude 70 mT is directed at 40° to the plane of the loop?
a. 66 A b. 89 A c. 61 A d. 75 A e. 37 A