Gravitational Forces Flashcards
(31 cards)
Newton’s First Law
(Law of Inertia) an object in motion tends to stay in motion & an object at rest tends to stay at rest unless acted upon by an outside force.
Newton’s Second Law
Force = Mass x Acceleration
Newton’s Third Law
For every action there is an equal and opposite reaction
what is 1G (Gravity)
32.2 Ft/sec2
What is Inertia
the resistance to a change in the state of rest or motion
Acceleration
The (increased) rate of change of velocity with respect to time. Acceleration of gravity continues until terminal velocity is reached.
Deceleration
A reduction in the velocity of a moving body with respect to time (negative acceleration)
What is the Tri-axial Reference System
Identifies the direction in which the body receives accelerative forces. (X,Y, & Z axes)
X-axis
the axis through the chest to back
Y-axis
the axis across the shoulders
Z-axis
the long axis along the spine from head to foot
What are the factors of acceleration that affect severity of impact on the body
(BIRDI) Body Area and site Intensity Rate of onset Duration Impact direction
How do changes in body surface area affect injury severity?
increase body surface area = decreased severity
How do changes in intensity of acceleration forces effect injury severity?
increased intensity = increased severity
How do changes in rate of onset of acceleration forces effect injury severity?
increased rate of onset = increased severity
How do changes in duration of acceleration forces effect injury severity?
increased duration = increased severity
How does impact direction effect injury severity?
all other factor being equal, y-axis impacts will result in more severe injury than z- or x-axis impacts. +Gx impacts are the most survivable.
What are the factors that reduce the overall efficiency of the body to withstand G’s called?
Decremental factors
What are the factors that enhance the ability of the body to withstand G-forces called?
Incremental factors
Name some of the incremental and decremental factors with respect to +Gz
Decremental Factors: Dehydration, Alcohol Use, Blood Loss, Illness, Varicose Veins, Low Blood Pressure and Incremental Factors: Fear, Excitement, Asymptomatic Hypertension, G-suit, anti-G straining Maneuver
Aircraft design features that enhance crash survivability (CREEP)
- Container
- Restraints
- Environment
- Energy absorption
- Post crash factors
Occupant survivability during an accident sequence is contingent upon the what criteria?
The amount of crash forces transmitted and occupiable living space (Two objects cannot occupy the same space).
________ is the resistance to a change in the state of rest or motion.
inertia
________ is a reduction in the velocity of a moving body with respect to time.
deceleration
