AAMC 4&5 Specific Gravity

[folktale]

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AAMC 4 Discrete # 18

An object with 15 grams mass is immersed in benzene and suffers an apparent loss of mass of 5 grams. What is the approximate specific gravity of the object? (Sp. gravity of benzene = 0.7)

A. 1.4
B. 1.8
C. 2.1
D. 3.0

Answer C

I got this question right. I know that specific gravity usually is W/B or relative to the density of water. But I'm just wondering how would you compare the specific gravity of two liquids other than water?

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AAMC 5 Discrete #49

An object is totally immersed in benzene (sp. gravity = .7) is subject to a buoyancy force of 5N. When the same object is totally immersed in an unknown liquid, the Fb is 12 N. What is the approx. specific gravity of the unknown liquid?

A. 0.3
B. 0.9
C. 1.7
D. 2.3

Answer C

Can someone clarify this?

 

[pfaction]

Sure, I'll post what I did in an edit.

An object with 15 grams mass is immersed in benzene and suffers an apparent loss of mass of 5 grams. What is the approximate specific gravity of the object? (Sp. gravity of benzene = 0.7)

SUBMERGED.

Wobj / FBuoy = pobj / pliq

15 / 5 = pobj / 0.7
3:1 done!

An object is totally immersed in benzene (sp. gravity = .7) is subject to a buoyancy force of 5N. When the same object is totally immersed in an unknown liquid, the Fb is 12 N. What is the approx. specific gravity of the unknown liquid?

So basically I had to do some creative math.

Wobj/FBuoy = pobj/pliq
Wobj/5N=pobj/0.7

Wobj/12N=pobj/pliq
Well, wobj is the same, and pobj is the same, only thing we're looking for is the other thing.

Wobj(.7)/5N = pobj
Wobj(pliq)/12N = pobj
Set them equal to each other.

W(.7)/5 = W(pliq)/12
(.7)/5 = pliq/12
12/5 (.7)
2.4(.7) is above 1.4, less than 2.1!

 

[folktale]

That helps!

For the second one, can't you just do the ratios of the buoyancy forces and equal that to the specific gravity for each liquid as well?

Fb(liq)/Fb(benzene) = p(liq)/p(benzene)

Seems faster that way.

 

[sudo]

That helps!

For the second one, can't you just do the ratios of the buoyancy forces and equal that to the specific gravity for each liquid as well?

Fb(liq)/Fb(benzene) = p(liq)/p(benzene)

Seems faster that way.

That's how I went about solving that problem!👍

 

[MedGrl@2022]

AAMC 4 Discrete # 18

An object with 15 grams mass is immersed in benzene and suffers an apparent loss of mass of 5 grams. What is the approximate specific gravity of the object? (Sp. gravity of benzene = 0.7)

A. 1.4
B. 1.8
C. 2.1
D. 3.0

Answer C

I got this question right. I know that specific gravity usually is W/B or relative to the density of water. But I'm just wondering how would you compare the specific gravity of two liquids other than water?

------------
AAMC 5 Discrete #49

An object is totally immersed in benzene (sp. gravity = .7) is subject to a buoyancy force of 5N. When the same object is totally immersed in an unknown liquid, the Fb is 12 N. What is the approx. specific gravity of the unknown liquid?

A. 0.3
B. 0.9
C. 1.7
D. 2.3

Answer C

Can someone clarify this?

Is the answer to the second one C 1.7? I did the ratios Fb unknown/Fb benzene=S.G unknown/S.G benzene