Question

A solid iron ball and a solid aluminium ball of the same diameter are released together at the surface of a deep lake. Which ball will reach the bottom first?

• A. Aluminium ball
• B. Iron ball
• C. Both balls will reach the bottom at the same time
• D. The aluminium ball will never reach the bottom and will remain suspended in the lake

Answer 1

The correct option is B

Iron ball

Since both balls have the same volume, they experience the same upthrust. Since the density of iron is greater than that of aluminium, the iron ball has a greater mass and therefore a greater weight; it therefore accelerates more and will reach the bottom before the aluminium ball.