A solid rock, suspended in air by a spring scale, has a measured mass of 9.00 kg. When the rock is submerged in water, the scale reads 6.43 kg. What is the density of the rock? (water density = 1000 kg/m³)

Question

Quizplus · Accepted Answer

The buoyant force equals the weight of the water displaced, which is the difference in scale readings (9.00 kg - 6.43 kg = 2.57 kg). The volume of the rock is the mass of water displaced divided by the density of water (2.57 kg / 1000 kg/m³ = 0.00257 m³). The density of the rock is its mass divided by its volume (9.00 kg / 0.00257 m³ = 3500 kg/m³ or 3.50 x 10³ kg/m³).

A Solid Rock, Suspended in Air by a Spring Scale