why is the momentum constant if the mango drops from the tree without rebound
The momentum of an object is the product of its mass and velocity. According to the law of conservation of momentum, the total momentum of a system remains constant if no external forces act on it.
When the mango drops from the tree without rebounding, assuming no external forces like air resistance are acting on it, the only force acting on the mango is gravity. As it falls, the force of gravity accelerates the mango, increasing its velocity.
However, even though the velocity of the mango changes, its mass remains constant, and therefore the product of mass and velocity (momentum) also remains constant. This is because there are no external forces to change the momentum of the mango during its free fall.
To calculate the momentum of the mango at any point during its fall, you would need to know its mass and velocity at that moment. The initial momentum of the mango when it starts falling would depend on its initial velocity. As it falls, you could use the laws of kinematics and Newton's laws of motion to track its velocity and determine its momentum at different points in time.