Question

explain why some fruits may get detached from a tree if we vigorsously shake its branches​

Answer 1

The answer of this cause lies behind the Newton’s First Law of Motion. Initially, fruits and tree both are in rest. But when the tree is shaken vigorously, fruits comes in motion while fruits have tendency to be in rest. Thus, because of remaining in the position of rest some of the fruits may get detached from a tree if we vigorously shake its branch.

Answer 2

we say in short term ...(due to inertia of tree)