Question

A boat having a length of 3 metre and breadth 2 metre is floating on a lake. The boat sinks by 1cm when a man gets on it. The mass of the man is

• A. 60 kg
• B. 72 kg
• C. 128 kg
• D. 62 kg

Answer 1

The correct option is A 60 kg

According to the law of floatation.
Upthrust = weight of the liquid displaced
Weight of a man = weight of water dispaced
$\therefore$ Mass of the man = Volume $\times$ Density
= Area $\times$ Height $\times$ Density
$=3\times 2\times \frac{1}{100}\times {10}^3$
$=60kg$