Exam I Flashcards
(123 cards)
1st Law of Motion (Law of Intertia)
A body in motion tends to stay in motion unless acted on by another force.
2nd Law of Motion (Law of Acceleration)
Acceleration of a body is in the direction of and proportional to the force (f), and that acceleration (a) is inversely proportional to the mass (m) of the body.
F = m x a
3rd Law of Motion (Law of Reciprocal Action)
For every action, there is an equal and opposite reaction; objects exert opposite forces on one another.
First Law of Thermodynamics
Energy cannot be created or destroyed.
Second Law of Thermodynamics
Energy moves toward greater entropy or randomness.
Third Law of Thermodynamics
Absolute zero (0K or -273.15 C) is void of all energy.
As a system approaches absolute zero, all processes cease, and the entropy of a system approaches minimum value.
Force
The amount of energy required to move an object.
Force = mass x acceleration
Pressure
Force over an area. Increasing the area in which force is applied results in a lower pressure.
P = f / a
Work
Transfer of energy by a force acting on an object as it is displaced.
Work (w) = force (f) x distance (m)
Energy
The capacity to do work (potential energy) or the exertion of force (kinetic energy).
Power
The rate at which work is done.
Amount of energy transferred or converted per unit time.
Force SI Units
Newton = 102 g weight
Pressure SI Units
Pascal (Pa) = 102 g / 1 m2
Work SI Units
Joule
Energy SI Units
Joule
Power SI Units
Watts
Radiation
Electromagnetic transfer of energy away from a warm body.
Largest contributor to heat loss.
Convection
Heat creates air currents. Bodies transfer kinetic energy to air molecules on the surface of the skin. Warmed air molecules rise and colder molecules replace them.
The second largest contributor to heat loss.
Conduction
Transfer of heat via contact with a less warm object. Heat exchange from high concentration to low concentration.
Smallest contributor to heat loss.
Evaporation
Heat loss includes moisture evaporation from the patient’s skin and exhaled water vapor.
Latent heat evaporation is the amount of energy per unit mass required to convert a liquid into the vapor phase.
Mitigating Radiation in the OR
Cover the head, a major contributor to heat loss.
Mitigating Convection in the OR
Blankets, forced air warming device, prevent draft.
Mitigating Conduction in the OR
Warm OR table, cover the table with blankets.
Mitigating Evaporation in the OR
HMEs, only prep areas needed.