A wall is constructed of a 2 inch layer of fiberglass board (R = 8) and six inches of fiberglass batting (R = 19). If the temperature on the outside surface of the fiberglass board is 50°F and the temperature on the inside surface of the fiberglass batting is 68°F, what is the temperature (in °F) at the interface? (The units of R are ft2/°F/h/BTU.)
a. 62
b. 58
c. 55
d. 65
e. 52
c
You might also like to view...
A player throws a football 50.0 m at 61.0° north of west. What is the westward component of the displacement of the football?
A) 64.7m B) 55.0 m C) 0.00 m D) 74.0 m E) 24.2 m
A jet airliner moving at 470 mph due east moves into a region where the wind is blowing at 110 mph in a direction 30.0° north of east. What is the new velocity and direction of the aircraft?
a. 568 mph, 5.56° N of E b. 573 mph, 5.98° N of E c. 520 mph, 9.06° N of E d. 568 mph, 10.4° N of E e. 448 mph, 9.45° N of E
A charge Q is uniformly distributed along the x axis from x = a to x = b. If Q = 45 nC, a = ?3.0 m, and b = 2.0 m, what is the electric potential (relative to zero at infinity) at the point, x = 8.0 m, on the x axis?
a. 71 V b. 60 V c. 49 V d. 82 V e. 150 V
When we say charges are ‘positive' or ‘negative' we are speaking of
a. two intrinsically different types of charge found in nature b. an excess vs. a deficiency of charge c. charges existing vs. not existing d. none of the above