Fluids

Question 1

Give the relationship of density ρ of any material. Then give the same relationship where a material sample is much larger than atomic dimensions.

Answer 1

ρ = Δm / ΔV –> ρ = m / V

Question 2

A fluid is a substance that can ____; why does it conform to the boundaries of its container.

Answer 2

flow; it does not sustain to the shear stress of the material.

Question 3

Why are gases readily compressible and liquids are not?

Answer 3

the density of gases vary with pressure but the density of liquid does not.

Question 4

We define the pressure as what? Now find the limit of this ratio as the surface area is made smaller and smaller.

Answer 4

p = ΔF/ΔA –> p =F/A

Question 5

The pressure in a fluid is the same for all points at the same _______.

Answer 5

level or height.

Question 6

_______ pressure is the difference between the actual pressure (or absolute pressure) at a point and the atmospheric pressure.

Answer 6

Gauge

Question 7

Define static equilibrium.

Answer 7

Stationary and the forces on it balance.

Question 8

The pressure at a point in a fluid in static equilibrium depends on what? Does it also depend on any horizontal dimension of the fluid or its container?

Answer 8

Depends the depth of a point; No.

Question 9

Derive an equation that can be used to find pressure both in a liquid and in the atmosphere.

Answer 9

general: p = p_o + ρg(y₂ - y₁)
former: p = p_o + ρgh_depth
latter: p = p_o - ρgh_above

p is the total pressure at a point.

p_o is the atmospheric pressure.