Question

What is the bulk modulus for a perfect rigid body?

Answer 1

Formula Used: $B=\frac{\text{Stress}}{\text{volume strain}}$

Bulk modulus is given by

$B=\frac{\text{Stress}}{\text{volume strain}}=-\frac{p}{\frac{\Delta V}{V}}=-\frac{pV}{\Delta V}$

For perfectly rigid body, change in volume $\Delta V=0$, therefore volumetric strain is zero.

$\therefore B=\frac{pV}{0}=\infty$

Hence, bulk modulus for a perfectly rigid body is infinity.

Final Answer: Infinity.