Physics chap 4

Question 1

What is work and how do you calculate it?

Answer 1

• A force does work acting on an object and displace it in the direction of force
  W= F x D x cos (. )

W=work done
F=magnitude of the force
d= magnitude of displacement
.= angle between the force and displacement

Question 2

Work has what unit

Answer 2

SI units of joule

Question 3

One joule of work is used when a force of 1 Newton acts over a displacement of 1 meter.

Answer 3

1 J= 1N X m

Question 4

Work is the

Answer 4

act of force of an object, to displace the object in the direction of the force (direction/vector)
- work is not done if the object does not move over a distance

Question 5

Mass is the

Answer 5

total of all matter in an object (sum of all electrons, protons, and neutrons). Mass only has magnitude and is a scalar quantity.

measured in kilograms

mass=volume x density

Question 6

Weight is the

Answer 6

total effect of gravity pulling on all these electrons, protons, and neutrons of an object. Mass remains the same but weight decreases at moon surface

Measure of the amount of force acting on a mass due to acceleration due to gravityHas both magnitude and direction and is a vector quantity

measured in newtons

weight = mass x acceleration due to gravity

Question 7

SVR

Answer 7

900-1200 dynes/cm ^5

((MAP-CVP)/CO) x 80

Question 8

What is compliance? How is it related with elasticity?

Answer 8

Inversely related.

Question 9

What happens to lung compliance in emphysema?

Answer 9

• emphysema destroys elastic tissue
• compliance goes up

Question 10

What happens to lung compliance in pulmonary fibrosis?

Answer 10

Too much elastic tissue. Too tight. Stiff. Increased elastic tissue decreases compliance.

Question 11

Work=

Answer 11

pressure X volume

Question 12

Both inspiratory and expiratory work of breathing is performed by

Answer 12

diaphragm

Question 13

Energy is

Answer 13

exertion of force (kinetic) or the capacity (potential) to do work.

Can be expressed as mechanical work, chemical reaction or heat.

Energy is neither created nor destroyed, but only converted to other kinds of energy

Question 14

Kinetic energy

Answer 14

KE= 1/2mv^2
KE=
m=mass
v^2= velocity
KE=energy of motion/momentum

Question 15

Potential energy

Answer 15

is stored energy by virtue of position, waiting to be used

PE=mgh
(mass, gravity, height)
PE of a mass connected to an ideal string:
PE= kx^2
PE= stored energy/energy from gravity
k= spring constant and depends on the specific spring used

Question 16

Law of energy conservations states

Answer 16

the amount of energy in the universe is constant and is constantly being converted from one form to another

Question 17

1 calorie is needed to

Answer 17

raise the temperature of 1 gram of water by 1 degree Celsius

1 kcal= 4184 J

Question 18

W total=

Answer 18

change in KE= KE final-KE initial =mv^2 - mv^2 initial

Question 19

Entropy is the

Answer 19

universe’s trend to equilibrate all things. It is the process that allows: everything from ice melting to gas expansion and induction of general anesthesia by diffusion

Question 20

Power is the

Answer 20

rate of doing work or, conversaely, the rate of expending energy. Unit is watt

Question 21

Watt is the

Answer 21

capacity to do work

Question 22

Temperature is the

Answer 22

measurement of the thermal state of an object
Heat is thermal energy, temperature is the quantitative measurement of that energy

Question 23

Endothermic process

Answer 23

heat flows from the surroundings into the system

Question 24

Exothermic process

Answer 24

heat flows from the system out into the surroundings

Question 25

first law of thermodynamics

Answer 25

law of conservation of energy. energy cannot be created or destroyed.

Question 26

second law of thermodynamics

Answer 26

heat spontaneously flows from a hot body to a cold body when the two bodies are brought into thermal contact

Question 27

third law of thermodynamics

Answer 27

it is not possible to lower the temperature of an object to absolute zero

Question 28

Radiation is the

Answer 28

most significant mechanism of heat

Question 29

Convection is

Answer 29

heat loss by air current.

Question 30

Conduction

Answer 30

is transfer of heat by physically touching the objects

Question 31

Evaporation means

Answer 31

when water converts into gas form
- ex cleaning solution

Question 32

How much are you doing if you hold a 20 lb weight 3 ft above the floor?

Answer 32

no work

Question 33

How much are you doing if you lift a 20 lb weight 3 ft above the floor?

Answer 33

20 X 3 = 60 lbs

Question 34

Restrictive lung diseases

Answer 34

(pulmonary fibrosis; stiff lungs_ patients learn to minimize work of breathing by rapid and shallow breathing

Question 35

Obstructive lung diseases

Answer 35

COPD, resistance to flow;
patietns learn to minimize work of breathing by slowing and deep breathing. their problem is blowing the air out due to obstruction

Question 36

Minimize work of breathing by:

Answer 36

PEEP to keep lung volume at FRC (incentive spirometer)
-positioning
-surfactant
-optimizing respiratory rate
-increase laminar flow by heliox
-bronchodilators

Question 37

During inspiration,

Answer 37

about 1/2 the energy used is stored as PE in the elastic tissue fo the lungs and chest wall; active process.
this energy is then used during expiration to overcome airway resistance. this makes expiration a passive process
-

Question 38

resting membrane potential

Answer 38

makes nerve/muscle ready for action
-70 to 90 mV

Question 39

Joule (J) = ____ cal

Answer 39

0.239 cal

Question 40

Calorie (cal)= ____ J

Answer 40

4.184 J

Question 41

Watt hours (Wh) =_____ J

Answer 41

3,600 J

Question 42

Heat loss from greatest to least

Answer 42

1- Radiation
2- convection
3- evaporation
4- conduction

Question 43

Isotonic

Answer 43

work was done