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a. 1.4

b. 1.8

c. 2.1

d. 3.0

The answer is C but I really had trouble understanding how to solve this. This is AAMCs answer The buoyant force on an object immersed in a fluid displaced by the object (Archimedes principle)¸ There were 5 g of liquid displaced, thus, the ratio of object mass to fluid is 15/5 grams. The specific gravity of the object (mass per unit volume compared to water) is three times the specific gravity of benzene (3 x 0.7= 2.1) because the volumes of the object and displaced liquid are equal.

I am confused. 5 grams of benzene which has a specific gravity of 0.7 was displaced by an object, right? Thus, the apparent weight of the 15 grams object is 10 grams in fluid. Immersed could mean submerged or floating, right? The MCAT was being vague but since all of the answers are greater than 0.7 we can assume that the object is submerged, right? Thus, this object is displacing its volume in benzene and this volume displaced it equal to 5 grams of benzene, right? Is that why they are doing a ratio of the object mass to the fluid mass 15/5=3. It is saying that the specific gravity of the object is 3 times as great as benzene since it sank and weighs more than the fluid that it displaced. Therefore, that is why they multiplied 3 x 0.7= 2.1 because the object is more dense and the specific gravity of the object is 3 times that of benzene.

Did I figure this out correctly? What did AAMC mean when they said because the volumes of the object and displaced liquid are equal? Were they trying to explain the reason the object is more dense is because it weighs 15grams but only displaced 5grams of liquid?

I am going to redo all the EK 1001s on this subject but does anyone know of more practice problems on this subject. For some reason, I have been having issues in the past on this particular subject and I want to be able to answer them all correctly from now on. Also helpful tactics would be great.

Thank you!