16 - Non-Conservative Forces

# 16 - Non-Conservative Forces - Power For next time Re-read...

This preview shows pages 1–6. Sign up to view the full content.

Power For next time: Re-read Chapters 7 & 8 Homework: Chapter 7 : 36, 40, 54

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
Conservative forces We saw examples where the work was only dependent on the initial and the final position of the object. By definition we call a force conservative , if the work done by the force depends only on the initial and final positions and not on the path taken. We call such forces also internal forces.
Conservative forces • Work is independent of path • Work around closed path is zero • Gravitational force: 12 2 G mm FG r = • Spring force: S F kx = −∆

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
Potential energy Potential energy is the negative of the work done by the conservative force () 2 1 Gravitational potential energy y fi y PE PE PE mg dy ∆= − = −− f i x x x PE PE PE F dx [ ] 2 1 21 y y PE m gy m y = PE mgh = PE mgh =
Spring potential energy 0 x f i x fi x x PE PE PE F dx ∆= − = () 0 0 Spring potential energy x PE PE PE kx dx −− 2 0 1 2 PE kx Potential energy is the negative of the work done by the conservative force 2 0 1 2 PE kx =

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

### Page1 / 19

16 - Non-Conservative Forces - Power For next time Re-read...

This preview shows document pages 1 - 6. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online