Fluids

Question 0

Specific gravity

Answer 0

= density of substance/ density of water

Density of water is 1000kg/ m^3

Question 1

Density

Answer 1

= mass/ volume

Question 2

Force of gravity for fluids

Answer 2

= density * volume* gravity

Question 3

Pressure

Answer 3

= force acting perpendicular to surface/ area

= atmospheric pressure + hydrostatic pressure

Question 4

Hydrostatic gauge pressure

Answer 4

= density * gravity * depth

Pressure due only to the fluid in the tank

Question 5

Archimedes principle

Answer 5

Buoyant force= density of fluid * volume submerged* gravity
If density of object< fluid density then :
the volume submerged = ( density of obj / density fluid)

An obj denser than the fluid will sink
The apparent weight =obj weight( density of obj * volume * gravity)- buoyant force

Question 6

Pascal law

Answer 6

A confined fluid will transmit an externally applied pressure equally

( force1/area1)= (force2/area2)

Area1* depth 1= area2* depth2

Force 1* depth1= force2 * depth 2

Question 7

Flow rate

Answer 7

= area * speed of flow

Area1* flow speed1= area2* flow speed 2

Question 8

Bernoulli principle

Answer 8

1. Fluid is incompressible
2. Laminar flow
3. Negligible viscosity
4. Steady flow rate

Pressure at point 1 + (density * gravity * height1) + (0.5 * density* flow speed1^2)= Pressure at point 2 + (density * gravity * height2) + (0.5 * density* flow speed2^2)

The pressure is lower where the flow speed is greater

Question 9

Stress

Answer 9

Can be shearing( bending), compression, tension forces

Theses stresses cause strain( obj shape change)

Hooke’ s law: stress= modulus * strain( change in length/ original length)
Tension/compression= young modulus
Shear- shear modulus

Change in length= ( force * original length)/( area* modulus)