Which of the following must never be used as a grounding electrode?
a. a metal underground gas piping system
b. a metal in-ground support structure
c. a ground ring
d. a metal underground water pipe in direct contact with the earth for 10' (3 m)
a. a metal underground gas piping system
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A _____ jack arch is composed of only one full brick in height and laid in a soldier position.
A. common B. soldier C. single D. bonded
The heating capacity of a calorimeter is known to be 4 kJ/°C, with negligible uncertainty. The number of dietary calories (kilocalories) per gram of a substance is given by C=cH(?T)/m, where C is the number of dietary calories,H is the heating capacity of the calorimeter, ?T is the increase in temperature in °C caused by burning the substance in the calorimeter, m is the mass of the substance in grams, and c=0.2390 cal/kJ is the conversion factor from kilojoules to dietary calories. An amount of mayonnaise with mass 0.40 ± 0.01 g is burned in a calorimeter. The temperature increase is 2.75 ± 0.02°C.
a. Estimate the number of dietary calories per gram of mayonnaise, and find the uncertainty in the estimate. b. Find the relative uncertainty in the estimated number of dietary calories. c. Which would provide a greater reduction in the uncertainty in C: reducing the uncertainty in the mass to 0.005 g or reducing the uncertainty in ?T to 0.01°C?
What problem can be caused if liquid refrigerant enters the compressor?
What will be an ideal response?
Framing steel roof systems requires the same number and type of fasteners as framing roof systems with dimensional lumber
Indicate whether the statement is true or false