Question

The height of a mountain is $H$ and the density of its rock is $3\times 10^{3}kg/m^{-3}$ . If the elastic limit of the rock is $3\times 10^{8}N/m^{-2}$ , find the height of the mountain

• A. 50 km
• B. 30 km
• C. 8 km
• D. 10 km

Answer 1

Answer: (D)

Stress $=\frac{F}{A}$
$=\frac{mg}{A}=\frac{Vdg}{A}=\frac{AHdg}{A}=Hdg$
Elastic limit of the rock $=3\times 10^{8}N/m^2$
$3\times 10^8=Hdg$
$3\times 10^8=H\times 3\times 10^4$
$\Rightarrow H=10km$