Flashcards in Physics Class 3 Deck (25)

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1

## Heat vs Temperature

###
Heat is the transfer of non-mechanical energy between system & environment

- extensive property: depends on mass of material

Temperature is measure of average internal thermal energy of system

- intensive property: like density or colour

2

## When does the temprature increase?

### When you change the phase

3

## Zeroth Law of Thermodynamics

### When 2 substances are in contact, heat transfers between them until they achieve the same temperature (thermal equilibrium)

4

## 3 Modes of Heat transfer

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1. Conduction - heat transfer through solids in contact

2. Convection - heat transfer through fluid circulation

3. Radiation - heat transfer by emission/absorption of electromagnetic energy

5

## First law of thermodynamics

###
Internal energy of a closed system depends on how much heat energy is transferred into system & how much work system does on its surroundings

ΔE = Q - W

6

## Ideal Gas Law

### PV = nRT

7

## Isochoric

###
constant volume

ΔV = 0

ΔE = Q

8

## Isobaric

###
Constant pressure

ΔP = 0

ΔE = Q - PΔV

9

## Isothermal

###
Constant temperature

ΔT = 0

10

## Adiabatic

###
No heat transfer

ΔQ = 0

11

## Pressure

###
Distribution of force over an area

Formula: P = F / A

Units: N/m^2 = Pa (pascal)

1 atm = 100 kPa = 1000 Pa = 760 torr = 760 mmHg

12

## Second law of thermodynamics

### Entropy of an isolated system either stays the same or increases during any thermodynamic process

13

## What happens to entropy of closed system?

### It can decrease if the entropy of its surrounding environment increases by a greater amount because it exchanges energy with the outside environment

14

## What kind of system is the human body?

### Open system because it exchanges ENERGY and MATTER with its outside environment

15

## Density

###
Formula: ρ = m/v

Units: kg/ m^3

16

## Weight of fluid

### W = ρVg

17

## Specific gravity

###
sp. gravity = p / pwater

ρwater = 1000 kg/m^3

18

## Hydrostatic Gauge Pressure

###
- Pressure due to being immersed with fluid

Pgauge = ρfluid x g x Depth

Ptotal = Psurface + P gauge

19

## Buoyant Force

### Upward force exerted on object either partially or completely submerged in a fluid due to pressure difference between top & bottom of object (bottom pressure > top pressure)

20

## Archimede's Principle

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Magnitude of buoyant fore is equivalent to the weight of the fluid that's displaced by the object

Fb = ρfluid x Vsubmerged x g

21

## Flow rate

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volume of fluid moving through a particular cross-sectional area per unit time

Units: m^3/s

Formula: f = Av

* flow speed is constant

22

## Continuity

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For an incompressible fluid, density is constant so flow rate is constant

A1v1 = A2v2

23

## Ideal Fluid Flow Factors

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1. Incompressibility (density is constant)

2. Negligible Viscosity

3. Laminar flow

4. Flow rate is stead (closed system)

24

## Bernoulli's equation

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P1 + ρgy1 + 1/2pv^2 = P2 + ρgy2 + 1/2pv^2

Describes ideal fluid flow

25