The principle behind how these huge ships are able to float on water

The amount of water it displaces (shaded area ) weighs as much as the ship. The weight of the ship pulling down and the upthrust pushing up are equal and opposite forcers so the ship floats.

Explanation:

Now the weight of the ship is more than the maximum possible upthrust so it sinks to the buttom

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

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

the answer is ampere

the ampere is used to measure electricity. an ampere is a unit of electric current equal. a unit of measure for the flow of current in a circuit. one ampere is the amount of current flow provided when one volt of electrical pressure is applied against one ohm of resistance.