Technical Measurements Flashcards
7 cards from real CST practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Technical Measurements flashcards as text
From a benchmark at elevation 100.00 ft, the backsight is 4.25 ft and the foresight on point A is 6.10 ft. What is the elevation of A?
Answer: 98.15 ft
HI = 100.00 + 4.25 = 104.25, and 104.25 − 6.10 = 98.15 ft.
The combined curvature and refraction correction over a sight distance of 1 mile is approximately:
Answer: 0.574 ft
Combined C&R ≈ 0.574K² ft, with K in miles, so it is about 0.574 ft at 1 mile.
Keeping backsight and foresight distances equal in differential leveling mainly cancels:
Answer: Collimation error and curvature/refraction
Equal sight lengths make line-of-sight tilt and C&R effects equal and opposite.
The smallest graduation on a standard engineer's (Philadelphia) leveling rod is:
Answer: 0.01 ft
Engineer's rods are graduated in hundredths of a foot.
A pipe rises 3.60 ft over a horizontal run of 240 ft. What is its grade?
Answer: 1.5%
Grade = 3.60/240 × 100 = 1.5%.
In three-wire leveling, the upper and lower stadia readings are 5.62 and 4.38. With a stadia constant of 100, the sight distance is:
Answer: 124 ft
Stadia interval 1.24 × 100 = 124 ft.
Why does the rod person slowly wave the rod toward and away from the instrument?
Answer: So the lowest reading, which is the plumb position, can be read
A tilted rod always reads too high, so the minimum reading is the plumb one.