Chapter07

# Chapter07 - Chapter7:PotentialEnergy Potential energy The...

This preview shows pages 1–7. Sign up to view the full content.

Chapter 7: Potential Energy  and Energy Conservation

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

View Full Document
About Potential Energy Potential energy The energy stored within a physical system as a result of the position or configuration of the different parts of that system. It has the potential to be converted into other forms of energy, such as kinetic energy, and to do work in the process. The potential energy is a function of the state a system is in, defined relative to an arbitrary reference energy.
1. Gravitational Potential Energy Work done by gravity Gravitational potential energy (near Earth’s surface) Then, W gravity = r F r s = ( - mg ö j ) (( y 2 - y 1 ) ö j ) = mgy 1 - mgy 2 U mgy = 1 2 2 1 ( ) gravity W U U U U U = - = - - = -∆

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

View Full Document
Conservation of Mechanical Energy For gravitational force 2 1 2 1 ( ) gravity tot W W K K U U = = - = - - 1 1 2 2 K U K U + = + constant E K U = + = Conservation of Mechanical Energy 2 1 2 E K U mv mgy = + = +
Since and , the potential energy is r ref is the position where the potential energy is zero For gravitational force at the Earth’s surface W U = -∆ W F dr = r r ref r r U F dr = - r r 0 ( ) y U mg dy mgy = - - =

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

View Full Document
Problem 7.5) A baseball is thrown from the roof of 22.0-m tall building with an initial velocity of magnitude 12.0 m/s and directed at an angle of 53.1° above the horizontal. a) What is the speed of the ball just before it strikes the ground?
This is the end of the preview. Sign up to access the rest of the document.

## This note was uploaded on 10/04/2011 for the course PHYS 2305 taught by Professor Tschang during the Spring '08 term at Virginia Tech.

### Page1 / 22

Chapter07 - Chapter7:PotentialEnergy Potential energy The...

This preview shows document pages 1 - 7. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online