Which describes who will record their measurements in joules? Lily and Henry
Astrid and Bob
Lily, Astrid, Henry, and Bob
Astrid, Henry, and Bob

Lily, Astrid, Henry, and Bob

Explanation:

By a small online search i've found the image related to this question, and you can see it below.

Joules is a unit of energy, such that:

Joule = kg*m^2/s^2

In other hand, Watt is a unit of power, such that:

1 W = 1 J/s

Then if we measure power, we are measuring watts, which is equivalent to measuring the total amount of energy in joules in a given period of time, and then dividing that by the time. And if we measure energy, we are directly measuring joules.

Then if we measure power or energy, at some point our measures will be in joules (unless we have an specific device to measure power, but these usually exist for electronic systems, not for mechanical/dinamic systems like the ones in the image), this means that all of them will record their measurements in joules, so the correct option is Lily, Astrid, Henry, and Bob

the minimum amperage that the current in this wire would have to have so that its weight is completely supported by the magnetic force due to earth's field, assuming that no other forces except gravity act on it