What is the definition of mechanical weather?

Answer 1

Mechanical (or physical) weathering is where physical forces (abrasion, exfoliation, frost action, root wedging) break the rock into smaller pieces but the composition of the rock is fundamentally unchanged.

in other terms:

Mechanical weathering is the process of erosion where larger rocks are broken down into smaller rocks without changing any of its chemical nature. The rocks are basically crashed by physical breakdown, rather than chemical. :)

Answer 2

Answer:

Mechanical Weathering-it causes rocks to be broken physically without changing their composition.