How could the interaction between the stove, the water, and the air be used to model the movement of energy between earths subsystems?

in simple terms, the principle states that the buoyancy force on an object is equal to the weight of the fluid displaced by the object, or the density of the fluid multiplied by the submerged volume times the gravitational acceleration, g. this is also known as upthrust.

if the person is shown to have +90n, then ans is -10n.

if the person is shown to have -90n, then ans is +10n.

t = 1/400 h   ⇔ 0.0025 h ⇔ 9s ⇔ 0.15 m

any of the answers are correct.