Sob:
Sobbing is an intense and audible expression of strong emotion, often accompanied by deep, convulsive breaths, and loud, uncontrollable sounds.
Example:
She couldn't control her sobs as she received the heartbreaking news of her pet's death.
Each sob wracked her body, and her cries echoed through the room.

Weep: 
Weeping is a quieter and gentler form of crying, typically characterized by tears flowing down one's cheeks without loud or intense sounds.
Example:
As she read the heartfelt letter from her long-lost friend, tears began to well up in her eyes, and she quietly wept, touched by the memories and emotions it evoked.

Cry: 
Cry is a broad term that encompasses a range of emotional expressions involving tears. It can refer to both intense and less intense forms of crying.
Example:
When the baby woke up in the middle of the night and needed a diaper change, she began to cry softly, signaling her discomfort. Later, when the baby was still hungry, she escalated her cries into loud, demanding sobs.

In summary, "sob" involves intense and audible crying with convulsive breaths and loud sounds, "weep" is a gentler form of crying with tears flowing quietly, and "cry" is a broad term that can encompass various levels of emotional expression involving tears, from soft cries to intense sobs