Two Marks Questions with Answers

Two Marks Questions with Answers

Q.1

Write the S.I. units of the mass moment of inertia and of the area moment of inertia of a lamina.

Ans. : 

S.I. unit of mass moment of inertia is kg-m2 and of area moment of inertia of a lamina is m4.

Q.2

Differentiate between area moment of inertia and mass moment of inertia.

Ans. : 

Area moment of inertia about any axis is the product of area and square of the distance of its centroid from that axis. Mass moment of inertia about any axis is the product of mass and square of the distance of its centroid from that axis. Area moment of inertia is defined for plane areas and its S.I. unit is m4. Mass moment is defined for all bodies and its S.I. unit is kg-m2.

Q.3

Define mass moment of inertia of a particle about an axis.

Ans. : 

Mass moment of inertia of a particle about an axis is the product of its mass and square of its distance from the axis.

Q.4

Define radius of gyration.

Ans. : 

Radius of gyration of a body can be defined as the distance of the point from the axis at which the whole mass of the body can be considered to be concentrated so that the mass moment of inertia remains unchanged.

Q.5

State parallel axis theorem.

Ans. : 

The mass moment of inertia of a body about any axis is equal to the sum of the mass moment of inertia about a parallel centroidal axis and the product of mass and square of the distance between the two parallel axes.

Q.6

State the relationship between the second moment of area and mass moment of inertia for a uniform plate.

Ans. : 

For second moment of area,

For mass moment of inertia,