Question

why physics is a basic science?

Answer 1

Physics is a basic science because it underlies the phenomena of many other disciplines. For example, it explains how chemistry works (which in turn explains how biological functions occur). It explains how materials react to forces, thus underpinning how engineering works. It explains how electromagnetic forces effect matter explaining how electronics work.

Also scientifically, complicated models can be built up from basic physical principles. These models can then be tested through experimentation and observation, and refined further.

This is my opinion of course, but I am extremely biased being a physicist. But Wiki seems to agree with me, and puts it in a better way to understand than I have managed http://en.wikipedia.org/wiki/Fundamental_science