Question

A tank of size $10m\times 10m\times 10m$ is full of water and built on the ground. If $g=10m{s}^{-2}$, the potential energy of the water in the tank is:

• A. $5\times {10}^7$ J
• B. $1\times {10}^8$ J
• C. ${10}^4$ J
• D. ${10}^5$ J

Answer 1

Answer: (A)

$5\times {10}^7$ J

The mass of $1cubicmeter$ of water $=1000kg$

So, the mass of $10\times 10\times 10$ $cubicmeter$ of water $=$

${10}^6$ $kg$

So, $PE=$ $mgh$ $={10}^6$ $\times 10\times 5$, ($5m$ is the height of the mid point of the tank)

So, $PE=5\times$ ${10}^{7}J$