* Gravity (Fg): This force acts downward, pulling the mass towards the center of the Earth. It's calculated as Fg = mg, where 'm' is the mass and 'g' is the acceleration due to gravity (approximately 9.8 m/s²).

* Spring Force (Fs): This force acts upward, opposing the displacement of the spring. It's calculated as Fs = -kx, where 'k' is the spring constant (a measure of the spring's stiffness) and 'x' is the displacement of the spring from its equilibrium position. The negative sign indicates that the spring force acts in the opposite direction to the displacement.

In addition to these main forces, other forces might be present depending on the specific situation:

* Air Resistance (Fair): This force acts upward, opposing the motion of the mass through the air. It depends on the mass's velocity and the shape of the object.

* Friction (Ff): If there is any friction between the mass and its point of suspension, this force acts to oppose the motion of the mass.

Equilibrium:

When the mass is hanging at rest, the forces are balanced:

* Fg = Fs

* mg = kx

This means the gravitational force pulling the mass down is equal to the spring force pulling the mass up.