A sample of metal weighs 219 gms in air, 180 gms in water, 120 gms in an unknown fluid. Then which is correct statement about density of metal
A. Density of metal can’t be determined
B. Metal is twice as dense as water
C. Metal will float in water
D. Metal is twice as dense as unknown fluid
Answer: Option A
This Question Belongs to Civil Engineering >> Strength Of Materials
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The weight of a body is due to
A. Centripetal force of earth
B. Gravitational pull exerted by the earth
C. Force of attraction experienced by par-ticles
D. Gravitational force of attraction towards the centre of the earth
The product of either force of couple with the arm of the couple is called
A. Resultant couple
B. Moment of the forces
C. Resulting couple
D. Moment of the couple
A. Density of metal can’t be determined
B. Metal is twice as dense as water
C. Metal will float in water
D. Metal is twice as dense as unknown fluid
Coulomb friction is the friction between
A. Bodies having relative motion
B. Two dry surfaces
C. Two lubricated surfaces
D. Solids and liquids
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option D is Correct
Here weight of metal 210g, water 180g , unknown fluid /liquid 120g
Relative Density of metal = weight in air / weight in air - weight in water
Relative Density of metal = 210/210-180 = 7
Also,
Relative Density of metal = Density of metal / Density of water
Density of metal = 7 * (density of water)
Density of meta = 7 * (1 g/cm^3) = 7 g/cm^3
Now,
Relative Density of Liquid = weight in air - weight in liquid / weight in air - weight in water
Relative Density of Liquid= 210 - 120 / 210 - 180 = 3
Also,
Relative Density of Liquid = Density of Liquid / Density of water
Density of Liquid = 3 * (density of water)
Density of Liquid = 3 * (1 g/cm^3)
Density of Liquid = 3 g/cm^3
So,
1) Weight of water is given so density can be determined
2) Relative density of metal is greater than 1 , so metal will sink
3) Density of metal is 7 g/cm^3 and water is 1 cm^3 so metal is 7 times denser than water
4) Density of Metal = 7 g/cm^3 & Density of Liquid = 3 g/cm^3
so, Density of Metal ~ 2 * Density of Liquid
so D is correct option
Density of the metal is 5609.8461 kg/m3 & that of the fluid is 2536.6153 kg/m3, density of metal/ density of fluid =2.21(approx 2),so option (d) seems correct
metal density is 5.6 g/cc, so it is 5 times denser than water, so it will not float in water. the unknown fluid density is 2.5 g/cc. so none are correct
Density of metal can we known as density of water is olways known so given answer is wrong
density of water is known to us. so density of metal can easily be calculated