Question

$Y,k,n$ represent respectively the young's modulus,bulk modulus and rigidity modulus of a body. If rigidity modulus is twice the bulk modulus, then:

• A. $Y$=$5k/18$
• B. $Y$=$5n/9$
• C. $Y$=$9k/5$
• D. $Y$=$18k/5$

Answer 1

The correct option is D $Y$=$18k/5$

$\frac{y}{n}+\frac{y}{3K}=3$ (standard result)
if $n=2K$
$y=3\left(\frac{n\times 3K}{n+3K}\right)$ $=\frac{18K^2}{5K}$
$y=\frac{18K}{5}$