What force must be applied to a steel anchor with a mass of 780 kg and a density of 7800 kg / m3

What force must be applied to a steel anchor with a mass of 780 kg and a density of 7800 kg / m3 in order to raise it to the surface of the water?

Initial data: m (weight of the steel anchor) = 780 kg.

Reference values: ρ1 (density of anchor, steel) = 7800 kg / m3; ρ2 (water density) = 1000 kg / m3; g (acceleration due to gravity) ≈ 10 m / s2.

The force that must be applied to the steel anchor to hold it in water is determined by the formula: F = Fт – Fa = m * g – ρ2 * g * V = m * g – ρ2 * g * m / ρ1 = m * g * ( 1 – ρ2 / ρ1).

Calculation: F = 780 * 10 * (1 – 1000/7800) = 6800 N (6.8 kN).

Answer: A force of 6.8 kN must be applied to the steel anchor.