The process that occurs when physical forces break rock into smaller pieces without changing the rocks chemical composition is called ?

Answer : Mechanical weathering.

Explanation : The process that occurs when physical forces break the rock into smaller pieces without changing the rocks chemical composition is called as mechanical weathering.

This process usually occurs near the surface of the earth, where high temperature affects the land. The cool nights and hot days are often the reason for things to expand and contract. This movement can cause rocks to crack and break apart into tiny small pieces. There is no new substance obtained it is just a physical change which does not involves any chemical compositional changes in it.