Civil Engineering - Hydraulics - Discussion

Discussion Forum : Hydraulics - Section 4 (Q.No. 44)
44.
A body of dimensions 1.5 m x 1.0 m x 2 m weighs 3000 kg in water. Its specific gravity is
0.8
0.9
1.0
1.1
Answer: Option
Explanation:
No answer description is available. Let's discuss.
Discussion:
27 comments Page 1 of 3.

ShreyaGiha said:   5 years ago
Weight in water = Weight in air - Buoyant force.
=>3000 = W- 1000*(1.5*1*2) = W-3000.
=>W = 6000kg.
Specific Gravity = 6000/1000*(1.5*1*2) = 2.

Weights should be expressed in N and mass in kg. As in the question, weight is expressed as kg, I have also taken it in kg. Even if it is converted to 'N', the answer would be the same 2. because g will be cancelled in both the cases
(6)

Bikram said:   2 years ago
1.0 is the correct answer.

The specific weight of fluid /specific weight of water =specific gravity.

Therefore,
The Specific weight of fluid=ρ*g.
10* (3000/1. 5*1*2) =10000.
Specific gravity=10000/10*1000=1.
(2)

Viral said:   7 years ago
Weight in air=weight in water + buoyant force.
=3000+(sp gr of water* g * volume displaced).
=3000+(1000*10*3).
=33000 N.

So,
Mass of body=33000/10.
=3300 kg.

Density=3300/3.
=1100.

Sp gr.=1100/1000.
=1.1.
(1)

Wazeer Baloch said:   8 years ago
Specific Gravity is not about to density to density. It's about sp weight to sp weight. Density is 1000unit but Sp Weight is 981.

Now,
1000/1000 = 1 answer is correct.

Arya said:   8 years ago
Density = mass/volume.

Density of the body = 3000/(1.5*1*2) = 1000kg/m^3.
Sp.gravity of the body = density of the body/density of water.
Sp.gravity = 1000/1000 = 1.

Shailendra kumar said:   9 years ago
It is exactly 1.0 not 1.1.

Sp gr. = density of object ÷ density of std fluid.

Therefore density of object is 3000/3 = 1000.
Hence sp gr = 1000 ÷ 1000 = 1.
(1)

Ifrah said:   3 years ago
Yes, you are right @iralHere weight in water is not 3000kg but 3000N. In this way, the answer will be 1.1
(2)

Amit sharma said:   8 years ago
Here, mass/volume is density =1000kg/m'3 specific density is 1000/981 = 1.1.

Myank said:   7 years ago
I think if the weight is in kg then G=2.0 but it is in N then G=1.1.
(1)

Ajay said:   7 years ago
I think it should be 1 because 981Value is not used anywhere.


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