Techniques and Procedures I RC 170. Basic Physics For Respiratory Therapist. Energy. Energy - the ability to do work Work = force X distance Kinetic energy - energy that an object possesses when it is in motion.
Figure 1-1 States of Matter
1 ATM = 760 mmHg = 14.7 psi = 1034 cmH2O
1mmHg = 1.36 cmH2O
Boiling point: temperature at which a liquid converts to a gaseous state
Figure 1-3 Temperature Scales
Freezing point: temperature at which change occurs from a liquid
to a solid
Figure 1-4 A mercury barometer
Figure 1-5 An aneroid barometer
(Page 103 Egan: Table 6-3)
Figure 1-6 A practical example of buoyancy.
Archimedes’s Principle: when an object is submerged in a fluid, it will
be buoyed up by a force equal to the weight of the fluid that is
displaced by the object……if the weight density of the object being
submerged is less than the weight density of the water, the object
Figure 1-8 The molecular basis for surface tension
Surface Tension: cohesive forces between liquid molecules at a gas-
liquid interface. Box 1-5 Adhesive and Cohesive forces.
Laplace's Law: the pressure within a sphere
is directly related to the surface tension of
the liquid and inversely related to the radius
of the sphere
Surface Tension forces cause a liquid to
have the tendency to occupy the smallest
possible area, which is usually a sphere.
Figure 1-9 Laplace's law.
Figure 1-10 Boyle’s Law
Figure 1-11 Charles's law
Figure 1-12 Gay-Lussac’s law
Combined Gas Law
PO2 = (760) (0.21) PO2= 159 mm Hg
PB= PO2+ PN2 + PCO2 + P (trace gases)
PB= (760)(0.21)+ (760)(0.78)+ (760)(.003)+ (760)(.07)
PB = 760 mm Hg
Figure 1-14 Fick’s law of diffusion
Figure 1-17 The Venturi principle