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Chapter 5 Upthrust In Fluids Archimedes Principle And Floatation | Exercise 5B

Question 27

A body of mass 70kg, when completely immersed in water, displaces 20,000 cm3 of water.

Find: (i) the weight of the body in water and (ii) the relative density of material of the body.

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Mass of the body = 70kg

Volume of water displaced = 20,000 cm3 or 0.02 m3

(i) To find the weight of the body submerged in water

Mass of the solid immersed in water= mass of the water displaced

= volume of water displaced x density of water = 0.02 x 1000 = 20kg

Weight of the body, W = mg

Weight of the body in water = (70 x 9.8) – (20 X 9.8) = 50 kgf

(ii) Density in C.G.S = mass/volume = 70 x 1000/ 20000 =3.5 g cm3

Relative density of the solid = density in C.G.S without unit = 3.5

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Question 27

A body of mass 70kg, when completely immersed in water, displaces 20,000 cm3 of water.

Find: (i) the weight of the body in water and (ii) the relative density of material of the body.

Looking to do well in your science exam ? Learn from an expert tutor. Book a free class!

Mass of the body = 70kg

Volume of water displaced = 20,000 cm3 or 0.02 m3

(i) To find the weight of the body submerged in water

Mass of the solid immersed in water= mass of the water displaced

= volume of water displaced x density of water = 0.02 x 1000 = 20kg

Weight of the body, W = mg

Weight of the body in water = (70 x 9.8) – (20 X 9.8) = 50 kgf

(ii) Density in C.G.S = mass/volume = 70 x 1000/ 20000 =3.5 g cm3

Relative density of the solid = density in C.G.S without unit = 3.5

Our top 5% students will be awarded a special scholarship to Lido.

subject-cta
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