# Problem 06 - Variation of Pressure

**Problem**

If the pressure in the tank of oil (sp gr 0.80) is 60 psi, what is the equivalent head: (a) in feet of oil, (b) in feet of water, and (c) in inches of mercury?

**Problem**

If the pressure in the tank of oil (sp gr 0.80) is 60 psi, what is the equivalent head: (a) in feet of oil, (b) in feet of water, and (c) in inches of mercury?

**Problem**

At what depth in a stand pipe containing water is the pressure 200 kPa?

**Problem**

What height of mercury column will cause a pressure of 680 kPa? What is the equivalent height of water column?

**Problem**

Take sea water to be 3% heavier than fresh water and assume it is incompressible. What is the pressure, in metric ton per square meter, at 3.22 km below the surface of the ocean if fresh water weighs 9.79 kN/m^{3}?

**Problem**

Determine the pressure on the face of a dam at a point 12 m below the water surface, in (a) kilo Pascal gauge; (b) kilogram per square meter gauge; (c) kilo Pascal absolute; (d) pounds per square foot gauge; (e) pounds per square inch gauge; and (e) pounds per square inch absolute.

**Problem**

Determine the pressure in a vessel of mercury, specific gravity 13.6, at a point 20 cm below the surface. Express the answer in N/m^{2}.

Consider two points 1 and 2 lie in the ends of fluid prism having a cross-sectional area *dA* and length *L*. The difference in elevation between these two points is h as shown in Figure 02 below. The fluid is at rest and its surface is free. The prism is therefore in equilibrium and all forces acting on it sums up to zero.

Note: FFS stands for Free Fluid Surface which refers to fluid surface subject to zero gauge pressure.

**Unit Pressure**

Unit pressure or simply called pressure is the amount of force exerted by a fluid distributed uniformly over a unit area.

$p = \dfrac{Force, \, F}{Area, \, A}$

If the unit pressure is not uniform over the unit area, it can be expressed as the sum of differential pressure.

$\displaystyle p = \int \dfrac{dF}{dA}$

Since fluid at rest cannot resist shearing stress, pressure is always at right angle to the area where it is acting. It is also worthy to note that the total hydrostatic force *F = pA*, which can be found by cross multiplication.

**Situation**

The helical spring shown is axially loaded with a compression force P equal to 5 kN. The mean diameter of the spring is 100 mm and the wire used is 10 mm as indicated in the figure.

- What is the shear stress at A?
- What is the shear stress at B?
- On diameter AB, locate the point of zero stress measured from C.

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- Transfer Formula for Moment of Inertia Using Variance in STAT Mode
- If tan (3x) = 5 tan (x), what is the value of sin (x)?
- Round off 314.587321 into four significant figures
- Minimum amount of money that must be spent before three gumballs of the same color are dispense
- Calculate 0.5 + 0.5^2 + 0.5^3 + ... + 0.5^20
- In tossing a coin, what is the probability of getting three consecutive heads or tails
- Solve for x: 1/x + 1/(x + 2) = 1
- Angle of Elevation
- Maximum possible volume, given1200cm^2 of material, square base and open top
- What number x is greater than x^n?