The essential properties of medium for propagation mechanical wave are
1) inertia and mass
2) inertia and elasticity
3) Elasticity and volume
4) inertia and volume

(A) : Relative to an observer at rest in a medium the speed of a mechanical wave in that medium (1) depends only on elastic and other properties (such as mass density) of the medium. It does not depend on the velocity of the source. (B): For an observer moving with velocity v_(0) relative to the medium, the speed of a wave is obviously different from v and is given by v+-v_(0)

The moment of inertia of a uniform rod about a perpendicular axis passing through one end is I_(1) . The same rod is bent into a ring and its moment of inertia about a diameter is I_(2) . Then I_(1)//I_(2) is

The correct order in which the dimensions of time decreases in the following physical quantities A) Power B) Modulus of elasticity C) Moment of inertia D) Angular momentum

(A): The longitudinal waves are called pressure waves. (R): Propagation of longitudinal waves through a medium involves changes in pressure and volume of medium, when compression and rarefaction are formed.

The moment of inertia of a door of mass m , length 2 l and width l about its longer side is.

A metallic wire is stretched by suspending a weight of it. If alpha is the longitudinal strain and Y is its Young's modulus of elasticity, then slow that the elastic potential energy per unit volume is given by 1/2Yalpha^(2) .

If I_(1) is the moment of inertia of a thin rod about an axis perpendicular to its length and passing through its centre of mass and I_(2) is the moment of inertia (about central axis) of the ring formed by bending the rod, then the ratio of I_(1) to I_(2) is

If I_(1) is the moment of inertia of a thin rod about an axis perpendicular to its length and passing through its centre of mass and I_(2) is the moment of inertia of the ring about an axis perpendicular to plane of ring and passing through its centre formed by bending the rod, then

Assertion : Speed of mechanical wave in the medium depends on the velocity of source, relative to an observer at rest. Reason : Speed of mechanical wave is independent of the elastic and other properties such as mass density of the medium.

(A): Mechanical transverse waves can propagate only in medium with shear modulus of elasticity (B) : Longitudinal waves need bulk modulus of elasticity and are therefore possible in all media, solids, liquids and gases