HM FINAL EXAM QUESTIONS AND ANSWERS
Center of Mass - CORRECT ANSWER✅✅Point about which all particles of the body are evenly
distributed
- average location of all masses in the body
- AKA- Center of gravity
Center of Gravity - CORRECT ANSWER✅✅The resultant of the force of gravity applied to all of the
particles that form of the body
- located at a point where the sum of the torques for all those individual masses is zero
Resultant weight force - CORRECT ANSWER✅✅sum of all the individual masses and goes through the
center of gravity
Where is COG located? - CORRECT ANSWER✅✅at a point where the sum of the torques for all those
individual masses is equal to zero
General location of COG in Humans - CORRECT ANSWER✅✅- Vertically at the level of S2" vertebrae"
- ~1" below the umbillicus
- through the midline
- 55% of standing height
What will the COG in neural standing depend on? - CORRECT ANSWER✅✅1. Body build in adults
2. Age
3. Gender
Gender discrepancies in neural standing - CORRECT ANSWER✅✅Males:
- 55-57% of standing height
- Broader shoulders
- more upper body muscle mass
,- Android fat patterning
Females
- 53-55% of standing height
- wider hips
- gyroid fat patterning
Are human rigid bodies? - CORRECT ANSWER✅✅No, COG moves when limbs and torso change position
Base of support - CORRECT ANSWER✅✅area bound by the outermost regions of contact between a
body and the support surface
Center of pressure - CORRECT ANSWER✅✅point at which the force vector generated by the weight of
an object is applied to the contact surface (ground)
Stability - CORRECT ANSWER✅✅resistance to disruption of equilibrium
- i.e.: resistance accelerations
Balance - CORRECT ANSWER✅✅ability to control equilibrium
Stability and Equilibrium - CORRECT ANSWER✅✅All objects at rest are in equilibrium
- due to the fact that all forces acting on the body/object are balanced
Types of equilibrium - CORRECT ANSWER✅✅stable, unstable, neutral
Stable equilibrium - CORRECT ANSWER✅✅the center of gravity must be raised in order to disrupt
object
- requires more effort and greater movement
- it has to do with torque
, Unstable equilibrium - CORRECT ANSWER✅✅The center of gravity starts high and drops to a lower
point
- requires less energy
- as a result, it is less stable
Neutral equilibrium - CORRECT ANSWER✅✅Object's center of gravity does not change when the
object's position changes
Three most critical factors affecting stability - CORRECT ANSWER✅✅1. Size of base of support
2. Relation of the line of gravity to the base of support
3. Height of the center of gravity
Additional factors affecting stability - CORRECT ANSWER✅✅4. Mass of the body
5. Friction
6. segmental alignment
7. visual and psychological factors
8. physiological factors
How to find an object/body's COG - CORRECT ANSWER✅✅Useful methods for objects at or objects in
motion (performed in lab)
- reaction board method
- segmental method
Less precise methods
- balance method
suspension method
reaction board method - CORRECT ANSWER✅✅- uses the concept of static equilibrium where the sum
of the torques and the sum of the forces equals zero
- calculate where the forces must be located to balance the torques
- counter clockwise torques = clockwise torques
Center of Mass - CORRECT ANSWER✅✅Point about which all particles of the body are evenly
distributed
- average location of all masses in the body
- AKA- Center of gravity
Center of Gravity - CORRECT ANSWER✅✅The resultant of the force of gravity applied to all of the
particles that form of the body
- located at a point where the sum of the torques for all those individual masses is zero
Resultant weight force - CORRECT ANSWER✅✅sum of all the individual masses and goes through the
center of gravity
Where is COG located? - CORRECT ANSWER✅✅at a point where the sum of the torques for all those
individual masses is equal to zero
General location of COG in Humans - CORRECT ANSWER✅✅- Vertically at the level of S2" vertebrae"
- ~1" below the umbillicus
- through the midline
- 55% of standing height
What will the COG in neural standing depend on? - CORRECT ANSWER✅✅1. Body build in adults
2. Age
3. Gender
Gender discrepancies in neural standing - CORRECT ANSWER✅✅Males:
- 55-57% of standing height
- Broader shoulders
- more upper body muscle mass
,- Android fat patterning
Females
- 53-55% of standing height
- wider hips
- gyroid fat patterning
Are human rigid bodies? - CORRECT ANSWER✅✅No, COG moves when limbs and torso change position
Base of support - CORRECT ANSWER✅✅area bound by the outermost regions of contact between a
body and the support surface
Center of pressure - CORRECT ANSWER✅✅point at which the force vector generated by the weight of
an object is applied to the contact surface (ground)
Stability - CORRECT ANSWER✅✅resistance to disruption of equilibrium
- i.e.: resistance accelerations
Balance - CORRECT ANSWER✅✅ability to control equilibrium
Stability and Equilibrium - CORRECT ANSWER✅✅All objects at rest are in equilibrium
- due to the fact that all forces acting on the body/object are balanced
Types of equilibrium - CORRECT ANSWER✅✅stable, unstable, neutral
Stable equilibrium - CORRECT ANSWER✅✅the center of gravity must be raised in order to disrupt
object
- requires more effort and greater movement
- it has to do with torque
, Unstable equilibrium - CORRECT ANSWER✅✅The center of gravity starts high and drops to a lower
point
- requires less energy
- as a result, it is less stable
Neutral equilibrium - CORRECT ANSWER✅✅Object's center of gravity does not change when the
object's position changes
Three most critical factors affecting stability - CORRECT ANSWER✅✅1. Size of base of support
2. Relation of the line of gravity to the base of support
3. Height of the center of gravity
Additional factors affecting stability - CORRECT ANSWER✅✅4. Mass of the body
5. Friction
6. segmental alignment
7. visual and psychological factors
8. physiological factors
How to find an object/body's COG - CORRECT ANSWER✅✅Useful methods for objects at or objects in
motion (performed in lab)
- reaction board method
- segmental method
Less precise methods
- balance method
suspension method
reaction board method - CORRECT ANSWER✅✅- uses the concept of static equilibrium where the sum
of the torques and the sum of the forces equals zero
- calculate where the forces must be located to balance the torques
- counter clockwise torques = clockwise torques
