Centre of Gravity, Stability and Balance

Question 1

What is balance?

Answer 1

Equilibrium is controlled for a given purpose
* Ability to maintain a stable position

Question 2

What is stability?

Answer 2

The resistance to a disruption in equilibrium
* The ability to return to equilibrium or to its original
position after being displaced

Question 3

What body positions are most stable?

Question 4

What is Center of gravity/ center of mass (CoG/ CoM)?

Answer 4

Center of gravity/ center of mass (CoG/ CoM)- an imaginary point in the center of an object (for an object with homogenous density) through which the force of gravity acts
1)-homogenous object same composition throughout e.g a clock center of mass is in the middle
2) Center of mass may lie on the outside of the object based on its orientation which can change
e.g leg straight COM knee joint however leg is bent COM is on hamstring side
Phosbery flopp was created with this in mind Cof M above bar and above belly button

Question 5

Is CoG/ CoM) the same?

Answer 5

No- they are used internally to describe

COM- is a point where the entire weight of an object can be considered to act it is central to the object which puts an object in a balanced state/
the COG is the point over which the object can be perfectly balanced; the net torque due to gravity about that point is zero
-where most weight is concentrated

COG-In contrast, the COM is the average location of the mass distribution. If the object were given some angular momentum, it would spin about the COM.

Question 6

True or false COM lies only in the center of a homogeneous object?

Answer 6

False because an object still has a center of mass even if it changes orientation when weight is distributed unequally.

Question 7

What is center of gravity?

Answer 7

is the point where the whole weight of the body or object acts

Question 8

what are 3 methods of locating COG

Answer 8

1) Reaction Board: (Direct method/Static position)
2)Segmentation Method
3)3. Suspension Method

Question 9

what is an example of each method?

Answer 9

1) Reaction Board Method
The calculation of the location CG involves the
summations of torques acting on the platform support

2) Dynamic Movements
-body segmentations
-Uses previously determined data which shows the
location of CG and relative mass of each segment (as
% from the proximal end point of the segment.
-he CG of whole body can be found by summing the
vertical and horizontal weight forces of each segment to find the point about which they are all balanced

3. Suspension Method
   More commonly used for
   determining CG of objects
   Ex. tennis racquet

Question 10

what are the factors that affect stability?

Answer 10

1) object weight newtons second law
2) friction
3)base of support