FAA Aviation Mechanic General (AMG)Physics, Math and Fluid LinesHard
A spherical hydraulic accumulator has an internal diameter of 6 inches. Using the formula V = (4/3)πr³, what is the approximate internal volume of the accumulator?
- A113.1 cubic inches
- B226.2 cubic inches
- C56.5 cubic inches
- D84.8 cubic inches
Show answer & explanationAnswer & explanation
Correct answer: A. 113.1 cubic inches
The radius is half the diameter: r = 3 inches. V = (4/3)(π)(3³) = (4/3)(3.1416)(27) = 113.1 cubic inches. Using the diameter directly instead of the radius is a common error that doubles or halves the result.
Why the other options are wrong
- B. This doubles the correct volume.
- C. This is half the correct volume, from a radius/diameter mix-up.
- D. This results from using diameter squared incorrectly in the formula.
Sphere Volume Formula
The volume of a sphere is calculated as V = (4/3)πr³, where r is the radius; used for spherical accumulators and tanks.
- Radius = half the diameter
- V = (4/3)πr³
- π ≈ 3.1416 for calculations
Memory trick: 'Four-thirds pi r cubed' — the sphere's secret formula.