1J (Joule) is the unit of energy in the International System of Units (SI). Here's how to express it in terms of fundamental units:

* Mass (kg): 1 kg

* Length (m): 1 m

* Time (s): 1 s

The relationship:

1 J = 1 kg * m² / s²

Explanation:

* Work and Energy: A Joule represents the amount of work done when a force of one Newton (1 N) moves an object one meter (1 m) in the direction of the force.

* Newton (N): A Newton is the force required to accelerate a mass of 1 kg at a rate of 1 m/s².

* Combining the units:

* Work (W) = Force (F) x Distance (d)

* 1 J = 1 N * 1 m

* 1 J = (1 kg * 1 m/s²) * 1 m

* 1 J = 1 kg * m² / s²

Therefore, 1 Joule is equivalent to one kilogram-meter squared per second squared.