Ac cording to Archimede's principle, when a body is immersed wholly or partly in a liquid at rest, it loses some of its weight. The loss in weight of the body in the liquid is equal to weight of liquid displaced by the immersed part of the body. From this principle, the law of floatation, is dedcued which states : A body will float in a liquid, if weight of liquid displaced by the immersed part of the body is atleast equal to or greater then the weight of the body. Read the above passage and answer the following questions : (i) A boat having a lenght of 3 m and breadth 2m is floating on a lake. The boat sinks by 1 cm when a man gets on it. What is the mass of the man ? (ii) What values of life do you learn from the law of floatation ?

Explanation

(i) Ac cording to the law of flotation, weight of mas = Additional weight of water displaced by the boat `mxx g =V xx rho xx g =(l xx b xxt) rho g`
`m = (lxx bxxt) xx rho =(3xx2 xx 0.01)xx 10^3 = 60 kg` (ii) In day to day life, a body corresponds to any business we indulge in. Weight of body is the cost of establishment and weight of liquid displaced corresponds to the revenu generated. The business will stay afloat only when revenue generted is atleast equal to or greater then the cost of establishment. If the revenu generted is less then the establishment cost, the business is likely to sink, i.e., close down.