StudyBrixFree worksheets, study guides and courses

Physics · Grades 9–12

Buoyancy from displaced volume

Use the density of the fluid and displaced fluid volume, not the object’s density.

Make a worksheet

Rule and assumptions

Use the density of the fluid and displaced fluid volume, not the object’s density.

Fᵦ = ρgV

Worked examples

An object displaces 8 litres of fluid of density 1000 kg/m³. Use g = 10 N/kg and 1 litre = 0.001 m³. Find buoyant force. Round to 3 decimal places if needed. Answer in N.

Fᵦ = ρgV 1000 × 10 × (8/1000) = 80

80 N

An object displaces 37 litres of fluid of density 1100 kg/m³. Use g = 10 N/kg and 1 litre = 0.001 m³. Find buoyant force. Round to 3 decimal places if needed. Answer in N.

Fᵦ = ρgV 1100 × 10 × (37/1000) = 407

407 N

Try two questions

  1. An object displaces 1 litres of fluid of density 700 kg/m³. Use g = 10 N/kg and 1 litre = 0.001 m³. Find buoyant force. Round to 3 decimal places if needed. Answer in N.

  2. An object displaces 44 litres of fluid of density 1200 kg/m³. Use g = 10 N/kg and 1 litre = 0.001 m³. Find buoyant force. Round to 3 decimal places if needed. Answer in N.

Answers and reasoning

Answers and marking notes
  1. 7 N

    Fᵦ = ρgV 700 × 10 × (1/1000) = 7

  2. 528 N

    Fᵦ = ρgV 1200 × 10 × (44/1000) = 528

Further reading and review references

These are reference links, not copied exercises, institutional endorsement or proof of independent review.

Learning preview · independent educational and translation review required. Suggested grades are not official curriculum alignment.