Question

The element lead (Pb) has a density 11.3 times that of water. Copper (Cu) has a density 7.9 times the density of water. A 5 kg mass of lead and a 5 kg mass of copper are both completely submerged in a bucket of water. Which mass has the LARGER buoyant force acting on it?

A) The buoyant force on the lead mass is larger.
B) The buoyant force on the copper mass is larger.
C) The buoyant force is the same on both masses.

Answer 1

Answer:

The answer is B

Explanation:

Density of the element lead (Pb) is:

$d_{Pb} =11,3kg/dm^3$

Density of the element Copper (Cu) is:

$d_{Cu} =7,9kg/dm^3$

First we need o find the volume of both materials:

$V_{Pb}=5/11,3=440cm^3$

$V_{Cu}=5/7,9=630cm^3$

And the buoyant forces on elements are:

$P_{Pb}=440*1*9,81/1000=4,32N$

$P_{Pb}=630*1*9,81/1000=6,18N$