Why Does Density Affect Velocity of Sound?

[hasanhabibul]

we know velocity of sound through a matter is v=root(elastic constant/density) according to Newton. suddenly it comes to my mind why density is the denominator here...that means as density will increase velocity of sound will decrease..but in solid ,density is certainly high but velocity of sound is also high as example a velocity of sound through iron is 5221m per sec...my quetsion is why density is denominator in the equation ...

 

[Doc Al]

You can't just look at density alone--it's the ratio of bulk modulus to density that counts. Increased density alone adds inertia--making the particles harder to move.