ch5 - Chapter 5 Energy continued 1 Work and falling objects...

Info iconThis preview shows pages 1–15. Sign up to view the full content.

View Full Document Right Arrow Icon
Chapter 5 Energy ontinued continued 1
Background image of page 1

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

View Full DocumentRight Arrow Icon
Work and falling objects ystem a collection of objects A system is a collection of objects interacting via forces or processes at are internal to the ystem that are internal to the system 2
Background image of page 2
Potential Energy Energy associated with the position of an object Potential energy is a property of the system , not the object Scalar quantity SI units – J 3
Background image of page 3

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

View Full DocumentRight Arrow Icon
Gravitational Potential Energy Gravitational Potential Energy is the energy associated with the relative position of an object located near the Earth’s surface Objects interact with the arth through the earth through the gravitational force mgy PE g 4
Background image of page 4
Problem As an object is lowered into a deep hole in the surface of the Earth, which of the following statements must be assumed in regard to its potential energy? a) Increase b) Decrease ) emain constant c) Remain constant d) Cannot tell from the information given 5
Background image of page 5

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

View Full DocumentRight Arrow Icon
Work done by Gravity ) ( ) ( i f i f gravity y y mg PE PE PE W 6
Background image of page 6
eference Levels for Reference Levels for Gravitational Potential Energy A location where the gravitational potential energy is zero must be chosen hoice arbitrary - e choice is arbitrary the change in the PE is the important quantity etermined by convenience determined by convenience once the position is chosen, it must remain fixed 7
Background image of page 7

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

View Full DocumentRight Arrow Icon
Springs Found in everyday objects 8
Background image of page 8
Hooke’s Law Hooke’s Law gives the rce exerted by the force exerted by the spring = x F - k x F is the restoring force F is in the opposite pp direction of x k – spring constant SI Units N/m 9
Background image of page 9

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

View Full DocumentRight Arrow Icon
Potential Energy in a Spring Elastic Potential Energy elated to the work required to Related to the work required to compress a spring from its equilibrium position to some final, arbitrary, position x 2 1 kx PE 2 s 10
Background image of page 10
Spring Potential Energy, Example A) The spring is in equilibrium, neither stretched or compressed B) The spring is compressed, storing potential energy C) The block is released and the otential energy is potential energy is transformed to kinetic energy of the lock block 11
Background image of page 11

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

View Full DocumentRight Arrow Icon
ork- nergy Theorem Including Work Energy Theorem Including Gravity and a Spring W nc = KE - W c PE g is the gravitational potential energy ) ( ) ( ) ( , , , , i s f s i g f g i f nc PE PE PE PE KE KE W PE s is the elastic potential energy associated with a spring 12
Background image of page 12
Work-Energy Theorem, Extended In general, the work-energy theorem can be written as PE KE PE PE KE KE W i f i f nc ) ( ) ( PE will now be used to denote the total potential energy of the system 13
Background image of page 13

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

View Full DocumentRight Arrow Icon
Problem 5.20 When a 2.50- kg object is hung vertically on a certain light spring described by Hooke’s law, the pring stretches 2 76 cm spring stretches 2.76 cm.
Background image of page 14
Image of page 15
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 10/05/2009 for the course PHY 1603 taught by Professor Boudreaux during the Spring '08 term at The University of Texas at San Antonio- San Antonio.

Page1 / 65

ch5 - Chapter 5 Energy continued 1 Work and falling objects...

This preview shows document pages 1 - 15. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online