Archimedes Principle

[PAGuyana]

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Please help. This thing is driving me crazy. Can someone give me a simplified approach on how to do these problems? How does Buoyancy Force, apparent weight, actual weight and specific gravity all tie into this pox?

Thanks for your help in advance.

 

[engineeredout]

Two types of problems that you may see on an mcat.

#1: An object is floating on a liquid with a specific gravity of x.y, and z% of it is submerged. What is the specific gravity/density of the water?

The rule for this type of problem is % submerged = density object / density liquid.

Ex: Ball floating on water, 50% submerged. SG of water is 1, so ball has SG of .5, or 500kg/m^3 or .5g/cm^3.

#2: A X kg object with a SG of K is fully submerged in a liquid. The apparent weight of the object is Y kg. What is the density of the liquid?

Ex: 15 kg ball with SG of 9 in a liquid. Apparent weight of the object is 10kg.

This means that the liquid is pushing up with a bouyant force able to counteract 5kg. The rule for these problems is the bouyant force is equal to the weight of liquid displaced. 5 kgs of liquid are displaced by the 15kg ball, meaning the ball has a SG three times that of the liquid, so the liquid has a SG of 3

 

[ej37]

Two types of problems that you may see on an mcat.

#1: An object is floating on a liquid with a specific gravity of x.y, and z% of it is submerged. What is the specific gravity/density of the water?

The rule for this type of problem is % submerged = density object / density liquid.

Ex: Ball floating on water, 50% submerged. SG of water is 1, so ball has SG of .5, or 500kg/m^3 or .5g/cm^3.

#2: A X kg object with a SG of K is fully submerged in a liquid. The apparent weight of the object is Y kg. What is the density of the liquid?

Ex: 15 kg ball with SG of 9 in a liquid. Apparent weight of the object is 10kg.

This means that the liquid is pushing up with a bouyant force able to counteract 5kg. The rule for these problems is the bouyant force is equal to the weight of liquid displaced. 5 kgs of liquid are displaced by the 15kg ball, meaning the ball has a SG three times that of the liquid, so the liquid has a SG of 3

This is almost right, although its important to remember that weight is in Newtons, not kgs

 

[engineeredout]

This is almost right, although its important to remember that weight is in Newtons, not kgs

Bah, same difference. 😴

Nah you're right though. I was half alseep yesterday.