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Traditionally made of cast iron, steel or concrete, manhole covers can also be made of fiberglass-reinforced plastic, which offers corrosion resistance. Why are manhole covers round?
AnswerA round manhole cover is larger in diameter than the ring on which it sits, as well as it holds its shape through freeze-thaw cycles better than square openings which may skew becoming trapezoidal.
ARE 4.0 exam prep: SPD
The four types or classes of fire extinguishers are identified using a picture-label system according to the type of fire for which they are designed. Match the shape (square, triangle, circle, star) to the following choices:
A. Class A for ordinary combustibles
B. Class B for flammable liquids
C. Class C for electrical fires
D. Class D for metal fires
AnswerSquare=B, Circle=C, Triangle=A, Star=D ARE exam prep: Building Systems
E. thermal shock
AnswerD. buckling. Buckling in slender columns tends to take place before the normal stress exceeds the strength of the column material.
ARE 4.0 exam prep: SS