Flashcards in Test 2 Deck (84)

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1

## Define Work? What is the formula for work?

###
Work is defined as a measurement of force displacing an object:

W = F x d (Work is equal to force x distance)

2

## What is the SI unit of measurement for Work?

### Joules

3

## Other ways of expressing 1J?

###
1) 1J = N x m

2) 1J = kg x m^2/s^2

4

## If you have 1kg mass you want to accelerate at 1m/s^2 over a distance of 1m. How much energy do you need?

###
Since W = F x d and F = m x a;

Then W = (m x a) x d

W = (1kg x 1m/s^2) x 1m = 1J or 1kg/m^2/s^2

5

## How much work was done in Joules lifting a 100kg patient up to a distance of 0.02m straight up to place him onto the operating table?

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Since W = F x d;

1st change weight into newtons because weight is acted upon by gravity which is newtons. So, 100kg = 981N, (1kg = 9.81N)

Now, w = 981 X .02 = 19.62J (rounding up gives you 20J or 2 x 10^1J

6

## Define Kinetic Energy? what is the formula for it?

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Kinetic Energy is described as energy of motion or the energy a mass has by virtue of being in motion.

KE = 1/2 mass x velocity (KE = 1/2kg x (m^2/s^2))

7

## What is the SI unit of measurement for Kinetic Energy?

### Joules or (kg/m^2/s^2); same as Force

8

## What is the KE of a 55kg mass moving at 3.87 meters per second?

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KE = 1/2m x velocity^2

KE = 0.5 x 55kg x (3.87m/s^2)

KE = 27.5kg x 14.97m^2/s^2

KE = 411.675J

9

## What is the formula used to find the Work done by expanding gas?

### W = P x ΔV

10

## What is the formula used to find the volume of a cylinder?

### V = A x h (Volume = area x height)

11

## What is the SI units of measurement for volume?

### m^3

12

## How many Liters in 1 m^3?

### 1000L

13

## How much work is done when 2.5L of gas expands to 3L against 600 Pa?

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Since W = P x ΔV or W = P x (final volume - initial volume). Since 3L = .003m^3 and 2.5L = .0025m^3; then

W = 600 Pa x (3 x 10^-3m^3 - 2.5 x 10^-3m^3)

W = 600 Pa x (.0005)

W = 0.3 Pa x m^3

W = 0.30J (1J is equal to 1 Pa x m^3)

14

## How much work is done when a ventilator increases the volume of air in the body by 500mL using 600Pa of pressure?

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W = P x ΔV

W = 600Pa x .0005m^3 = .3J

15

## Define Calorie?

### A calorie is the amount of energy necessary to raise 1 gram of water 1 degree Celsius.

16

## Whats the difference between a calorie and a Calorie?

### Food Calories are actually kilocalories, written with a capitalized "C". So, one Calorie = 1 kilocalorie or 1000 calories.

17

## How many Joules are in 1 calorie?

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1kcal (1000 calories) = 4184J or

1J = .239 calories

18

## How many Joules in a 2000kcal daily diet?

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.239cal/1J = 2000kcal/xJoules. -->

.239x = 2000kcal (2,000,000 calories) --> x = 8,368,200J or 8.368 x 10^6J

19

## If a 1500kg truck is traveling down the highway, how fast (v) must it be going to have the same energy as 2000kcal?

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KE = 1/2m x v^2 --> V^2 = 2KE/m

v = sq. root of 2KE/m

v = sq. root of 2(8.37 x 10^6J)/1500kg

v = 106m/s or 237mph

20

## Convert 106m/s to mph

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1609m = 1 mile and 3600 secs in and hr

1690/106 = 15.17miles

3600secs/15.17miles = 237mph

21

## Define Potential Energy? Give examples?

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Energy that is stored by virtue of position (expressed in Joules). i.e.:

1) An airplane in the air

2) Chemical energy stored in food, glucose, or fat

22

## Define Internal Energy? How is Internal Energy represented in an equation?

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The sum of all the kinetic energy and potential energies of the particles in a system. It results from the state of the particles at the molecular level.

Represented by the letter "U"

23

## Define Thermodynamics?

### The study of how energy is converted from one form to another, and how it flows into and out of a system. A system could be a test tube, a gas cylinder, a patient, etc.

24

## What are the 4 Laws of Thermodynamics?

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1) The Zeroth Law of Thermodynamics

2) The First Law of Thermodynamics

3) The Second Law of Thermodynamics

4) The Third Law of Thermodynamics

25

## What is the Zeroth Law of Thermodynamics?

###
Says that if 2 systems are in a thermal equilibrium with a third system, then they are thermal equilibrium with each other.

Therefore, if the temperature of A = B, and B = C, then A =C.

26

## What is the First Law of Thermodynamics?

### The change in Internal Energy (U) of a system of heat (Q) flowing in or out of the system; and work (W) done by or on the system. (ΔU = Q - W) but is written as (ΔU = Q + W)

27

## Why is the 1st Law of thermodynamics written as ΔU = Q - W instead of ΔU = Q + W?

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Because heat and work can be added into or taken out of the system.

If Q > 0, the process is endothermic and heat flows into the system (+Q is used).

If Q < 0, the process is exothermic and heat flows into the system (-Q is used).

If W > 0, work done by system on surroundings aka expansion (-W is used).

If W < 0, work done by system on surroundings aka compression (-W is used).

28

## What is the 2nd Law of Thermodynamics?

### Says that entropy of the universe is constantly increasing. It does not become spontaneously more organized.

29

## Give an example of the 2nd Law of Thermodynamics?

### A mixture of oxygen and nitrous oxide in an anesthesia induction will not spontaneously separate and send only one gas to the patient.

30