parallel and perpendicular axis theorem
Answers
Answer:
Parallel axis theorem states that
The moment of inertia of a body about an axis parallel to the body passing through its center is equal to the sum of moment of inertia of body about the axis passing through the center and product of mass of the body times the square of distance between the two axes.
Parallel Axis Theorem Formula
Parallel axis theorem statement can be expressed as follows:
I = Ic + Mh2
Where,
I is the moment of inertia of the body
Ic is the moment of inertia about the center
M is the mass of the body
h2 is the square of distance between the two axes
Parallel Axis Theorem Derivation
Let Ic be the moment of inertia of an axis which is passing through the center of mass (AB from the figure) and I be the moment of inertia about the axis A’B’ at a distance of h.
Consider a particle of mass m at a distance r from the center of gravity of the body.
Then,
Distance from A’B’ = r + h
I = ∑m (r + h)2
I = ∑m (r2 + h2 + 2rh)
I = ∑mr2 + ∑mh2 + ∑2rh
I = Ic + h2∑m + 2h∑mr
I = Ic + Mh2 + 0
I = Ic + Mh2
Hence, above is the formula of parallel axis theorem.
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