A cylindrical rod of length 12 cm and diameter 2.0 cm will just barely float in water of density 1000 kg/m³.What is its mass?

Question

Quizplus · Accepted Answer

The buoyant force on the rod is equal to the weight of the water displaced by the rod. The volume of the water displaced is equal to the volume of the rod, which is:$$V = \pi r^2 h = \pi (1.0 	ext{ cm})^2 (12 	ext{ cm}) = 37.7 	ext{ cm}^3$$The mass of the water displaced is:$$m = ho V = (1000 	ext{ kg/m}^3)(37.7 	imes 10^{-6} 	ext{ m}^3) = 0.0377 	ext{ kg} = 37.7 	ext{ g}$$Therefore, the mass of the rod is 37.7 g.

A Cylindrical Rod of Length 12 Cm and Diameter 2