Universal law, g, free-fall, buoyancy, Archimedes, density/RD MCQs

Q1. A solid of mass 60 g and volume 50 cm³ is placed in water (density 1 g/cm³). Which statement is true?

• A.It sinks because its density (1.2 g/cm³) exceeds that of water.
• B.It floats with 50% volume submerged.
• C.It floats with 60% volume submerged.
• D.It remains stationary at any depth as it is in equilibrium.

Answer: A. It sinks because its density (1.2 g/cm³) exceeds that of water.

Given 60 g, 50 cm, 1 g, asked for the unknown. By Density = 60/50 = 1.2 g/cm³, which is greater than water's 1 g/cm³, so the solid sinks. Density = 60/50 = 1.2 g/cm³, which is greater than water's 1 g/cm³, so the solid sinks. Consequently option A) It sinks because its density (1.2 g/cm³) exceeds that of water.

Q2. The distance between two bodies is tripled and one of the masses is doubled. The gravitational force between them becomes what fraction of the original?

• A.2/9
• B.1/9
• C.2/3
• D.4/9

Answer: A. 2/9

Asked for the unknown; data is laid out in the stem. By The new force becomes 2/(3²) = 2/9 of the original. The new force becomes 2/(3²) = 2/9 of the original. Consequently option A) 2/9.

Q3. A ship floats with 80% of its volume submerged in sea water (RD 1.025). What percent of its volume will be submerged in fresh water?

• A.82%
• B.78%
• C.85%
• D.80%

Answer: A. 82%