Cambridge International AS & A Level · 4 · structured
Distinguish depth, pressure difference and absolute pressure
Distinguish depth, pressure difference and absolute pressure · Original GioPhysics question with a detailed, mark-by-mark answer guide.
- Demand
- demanding
- Marks
- 4
- Topics
- 1
- Answer
- Complete
A point in a stationary oil reservoir is 0.80m below the free surface. Oil density is 850 kg m⁻³, g=9.81m s⁻² and surface air pressure is 1.01×10⁵Pa. A narrow sloping tube reaches the point along a1.20m path.
- (a)
Calculate pressure increase below the surface and absolute pressure at the point. Explain which of 0.80m and1.20m belongs in the equation and why.
4 marks
Ready to self-mark?Reveal the detailed answer guide
(a)
Calculate pressure increase below the surface and absolute pressure at the point. Explain which of 0.80m and1.20m belongs in the equation and why.
List the given quantities with units, identify the required quantity, write the governing relationship before substituting, and keep extra digits until the final line so rounding does not distort the result.
- 1
Use Δp=ρgΔh with vertical height difference.
- 2
Compute 6670.8 Pa.
- 3
Add surfacepressure 101000 Pa for107670.8 Pa.
- 4
Depth measures vertical fluid-column weight effect; tube path length does not.
Complete marking guidance
Use these worked steps alongside the part-by-part answers. They explain the method and mark allocation; they do not add extra marks.
- (a) Use Δp=ρgΔh with vertical height difference.
- (a) Compute 6670.8 Pa.
- (a) Add surfacepressure 101000 Pa for107670.8 Pa.
- (a) Depth measures vertical fluid-column weight effect; tube path length does not.
Private on this device