Viva questions for moment of inertia
Answers
where
dI = moment of inertia of a particle
dm = mass of that particle
r = distance of that particle from axis of rotation
Question.1. Define moment of inertia.
Answer.
Moment of inertia of a mass about any reference axis is the second moment of the mass about hat axis.
Moment of inertia is also termed as the second moment of mass and is denoted by I.
I
Question.2. What do u mean by second moment of area?
Answer.
The product of the area and the square of the distance of the C.G. of the area from that axis is known as second moment of area. It is called second moment of area because we are taking moment of area about an axis twice.
Question.3. Define radius of gyration.
Answer.
The distance of a point where the whole area of a body is assumed to be concentrated from a given axis is called radius of gyration.
Question.4. State theorem of parallel axis.
Answer.
It states that the moment of Inertia of a lamina about any axis in the plane of the lamina is equal to the sum of the Moment of Inertia of that lamina about its centroidal axis parallel to the given axis and the product of the area of the lamina and the square of the perpendicular distance between the two axis.
Question.5. State theorem of perpendicular axis.
Answer.
The perpendicular axis theorem states that the moment of inertia of a plane figure about an axis perpendicular to the figure and passing through the centroid is equal to the sum of moment of inertia of the given figure about two mutually perpendicular axis passing through the centroid and lying in the plane of the given figure.
Question.6. State and prove theorem of parallel axis.
Answer.
It states that the moment of inertia of a lamina about any axis in the plane of the lamina is equal to the sum of the Moment of Inertia of that lamina about its centroidal axis parallel to the given axis and the product of the area of the lamina and square of the perpendicular distance between the two axis.