Answer to Question #223151 in Astronomy | Astrophysics for Sandra

Question

1kg of iron (density 7.8gm/cm³ and 1kg of aluminum (density 2.5gm/cm³) are thrown in a well. Which one will experience the greatest buoyant force?

A.Iron

B.Aluminum

C. Both will experience the same buoyant force

D. None

Answer 1

Explanations & Calculations

• The one having the greatest volume will experience the greatest buoyant force.

$\qquad\qquad \begin{aligned} \small V&=\small \frac{m}{\rho} \end{aligned}$

• Here the mass of both substances are the same, therefore, one having the smallest density will have the largest volume.
• It is the 1kg of Aluminum that has the largest volume.
• The buoyant force is given by $\small = V\rho g$
• Both will be sinking once fallen to water as the buoyant force may not be enough to keep them floating. But the buoyant force will be acting accordingly.
• Therefore, Aluminum would have the largest buoyant force acting on it.
• Therefore, the answer is B.

• But if both are set to float somehow by making their volumes larger enough, the answer is C.