Fluid Mechanics and Heat, Temperature, and Energy

Fluid Statics (Hydrostatics)

• Study of fluids at rest (not moving).

• Focuses on pressure, density, and buoyancy.

Fluid Dynamics

• S t u d y o f f l u i d s i n

motion.

• Focuses on flow rate,

Bernoulli’s principle,

and continuity equation.

Mass Density

A property of matter defined as the ratio of its mass (m) to its volume (V). It is denoted by the Greek letter rho (ρ) In equation form.

Pressure

A measure of the force exerted

per unit area.

increases

When the force increases, and the area stays the

same, pressure _________.

Decreases

When the area increases, and the force stays the

same, pressure _________.

Bouyancy

Upward force a fluid exerts on an object

Archimedes’ Principle

When an object is fully or partially immersed in a fluid, it experiences an upward buoyant force equal to the weight of the fluid

displaced by the object.

Sinks

Floats

Suspends/Partially Submerged

Daniel Bernoulli

Was a Swiss mathematician and physicist who discovered the relationship between the speed and pressure of fluids, known as Bernoulli’s Principle. His work helped explain how airplanes fly, blood flows, and how pressure changes in moving fluids.

Archimedes

Temperature

Defined as a measure of the average

kinetic of molecules making

up an object.

Heat

Is energy in transit from

one body to another due to a

difference in temperature.

Ralph H. Fowler

A British  physicist and astronomer, formulated the Zeroth Law of

Thermodynamics in 1931.

Zeroth Law of Thermodynamics

It states that two bodies are in thermal equilibrium if they have the same temperature

Thermal equilibrium

Is the condition in which two or

more objects in contact no longer exchange heat

because they have reached the same temperature.

Temperature scale

A system for measuring how

hot or cold something is. It’s based on reference points

and divisions between them. The most common scales

are:

First Law of Thermodynamics

Energy cannot be created or

destroyed. It can only change

forms.

Second Law of Thermodynamics

Heat always flows from hot to cold. Things naturally become more disordered.

“In an isolated system, entropy increases,

and the energy becomes more disordered”

Third Law Law of Thermodynamics

At absolute zero (0 K), a perfect

crystal has no disorder; everything

stops moving.

Physical Change

When a substance 

changes its former form or appearance, but no new substance is made.

• The change is usually

reversible.

• T h e c h e m i c a l

composition stays the

same.

Chemical Change

When a substance changes into a new substance with different

properties.

• The change is usually

irreversible.

• The chemical bonds

b e t w e e n a t o m s a r e

broken or formed.

Thermal Expansion

Latent heat

Isothermal Process