Centre of Mass and Gravity

Question 1

CoM

Answer 1

real or fictional where all mass of a body can be considered

Question 2

if force is applied through CoM…

Answer 2

no spin (linear)

Question 3

if force isn’t applied through CoM…

Answer 3

spin (rotation)

Question 4

Gravity

Answer 4

forces acting between masses

Question 5

CoG

Answer 5

conceptual point which would have same potential energy of the body and where the resultant gravity force passes

Question 6

moment

Answer 6

product of a force and perpendicular distance from line of action of force to pivot

Question 7

equipment used to find CoM

Answer 7

statograph - finds CoG and moments about 1 axis
reaction board - ‘’ about 2 axis

Question 8

statograph readings

Answer 8

d = distance between pivots
Fb= force due to board
R1= force at scale pivot point
Xb = distance to CoG of board

R1d = FbXb

Question 9

statograph and human readings

Answer 9

d = distance between pivots
Fb= force due to board
Xb = distance to CoG of board

Fh = force due to human
R2= force at scale pivot point
Xh = distance to CoG of human

R2d = (FbXb) + (FhXh)

Question 10

segmantal method

Answer 10

sum of moments of component weight forces about any pivot = moment of resultant moments about that pivot