Moments and center of mass.

Question

"Moment" in physics is given by "force X distance"

but as i was studying a topic "Moments and centers of mass" in the chapter "Applications of integral" it say here, that it is "Mass X distance"?

i.e center of mass (x̄) = Σ M_k X_k /ΣM_k

where Σ M_k X_k is "moment of system about the origin". and M_k is mass of system.

Answer 1

Both are correct expressions

When you say force due to a given mass = m* acceleration due to gravity = mg ( N )

and moment of force = Force * distance = MgX

When we talk o center of mass

MX _CM = m1x1+ m2 x2 + m3 X3 +...... Eq 1

if we multiply both sides with g for force

MgX_CM = m1gX1 + m2gX2 + m3gX3 +......... Eq 2

Both equation 1 and 2 give same results