When rain falls from the sky, what happens to its momentum

as it hits the ground? Is your answer also valid for Newton’sfamous apple?

An internal force is aforce exerted by one part of a system on another.

An external force is a force exerted on any part ofa system by something outside the system.

If thenet external force on a system is zero, the totalmomentum of the system$\overrightarrow{\mathbf{p}}$ (the vector sum of themomenta of the individual particles that make upthe system) is constant or conserved. Each componentof total momentum is separately conserved.

$\overrightarrow{\mathbf{p}}\mathbf{=}{\overrightarrow{\mathbf{p}}}_{\mathbf{A}}\mathbf{+}{\overrightarrow{\mathbf{p}}}_{\mathbf{B}}$

If$\mathbf{\sum }_{\mathbf{}}\overrightarrow{\mathbf{F}}\mathbf{=}\mathbf{0}$

Then

$\overrightarrow{\mathbf{p}}$= constant.

We can considerthe raindrop and earth together as a system. Since no external force is acting on the system so according to the conservation of momentum total momentum is conserved in other words momentum of the rain is transferred to the earth.

Whether the object is a raindrop or an apple net external force is zero. Therefore, the answer is also valid for Newton’s famous apple.