Which of the following is not a recognized grounding electrode in 250.52?
A. An underground metal water pipe in contact with the earth for 15 ft (4.5 m)
B. A 2 AWG copper wire 20 ft (6.0 m) long buried in a ditch at least 21?2 ft (750 mm) deep
C. A concrete-encased electrode consisting of 1?2-in. rebar that is 92 ft long and encased in
the center of a 6-in concrete footing.
D. A ground plate buried at 30 in. (750 mm) below the surface
B. A 2 AWG copper wire 20 ft (6.0 m) long buried in a ditch at least 21?2 ft (750 mm) deep
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Which of the following is the formula for calculating the surface area of a circle?
a. 2(?R2) + 2?R(L) b. ?R2 c. a2 + b2 = c2 d. none of the above
This individual was the leading proponent of a zoo in Philadelphia
a. Carl Hagenbeck b. Benjamin Franklin c. Alexander the Great d. Dr. William Camac
58.255 x 0.03 = ____.
A. 1.74555 B. 1.74565 C. 1.74665 D. 1.74765
A cylindrical part of diameter d is loaded by an axial force P. This causes a stress of P/A, where If the load is known with an uncertainty of ±10 percent, the diameter is known within ±5 percent (tolerances), and the stress that causes failure (strength) is known within ±15 percent, determine the minimum design factor that will guarantee that the part will not fail.
What will be an ideal response?