Hanging from a spring balance
An object hanging from a spring balance also stays still. Here two forces act on it.
Figure to be added
The force acting downward
The weight of the object, which arises from gravity. It always acts vertically downward.
The force acting upward
The upward force applied by the spring, which holds the object up instead of letting it fall to the ground.
Under these two forces the object stays still. That is, under those two forces the object is in equilibrium.
Observation
Read the balance and you find its reading is equal to the weight of the object. Were the spring's upward force greater than the weight the object would rise; were it smaller, the object would fall.
This is also how a spring balance works: what it measures is the force it itself applies upward — and in equilibrium that force equals the weight of whatever hangs from it.