Unit 5 - Work and Energy CHAPTER 8 CONCEPTUAL PHYSICS BOOK CHAPTER 6 PHYSICS BOOK.

Slides:

Advertisements

Similar presentations

Gravitational potential energy. Conservation of energy

Advertisements

Energy and its Conservation

Sect. 8-3: Mechanical Energy & It’s Conservation.

Conservation of mechanical energy Lecture Conservation of Mechanical Energy Under the influence of conservative forces only (i.e. no friction or.

Conservation of Energy

ENERGY TRANSFORMATION. ● The Law of Conservation of Energy states that energy cannot be created nor destroyed. ● Energy can be transformed from one form.

Regents Physics Work and Energy.

PHYS16 – Lecture 17 Energy Conservation: Springs October 18, 2010.

Physics 151: Lecture 16, Pg 1 Physics 151: Lecture 16 Today’s Agenda l Today’s Topics: çConservation of mechanical energy çNonconservative forces and loss.

Chapter 8 Potential Energy and Conservation of Energy.

1a. Positive and negative work

Work and Energy CHAPTER 6. A New Perspective on Motion  We have been analyzing motion through the perspective of Newton’s Laws dealing with acceleration,

Chapter 7: Work and Energy (Ewen et al. 2005) Objectives: Related kinetic and potential energy to the law of conservation of mechanical energy. Related.

Conservation of Energy November The conservation of energy.  In a closed system, energy is neither created nor destroyed. Energy simply changes.

Chapter 7 The Conservation of Energy. Consider an object dropped near the surface of the earth. If the distance is small then the gravitational force.

Chapter 6 Work, Energy, Power Work  The work done by force is defined as the product of that force times the parallel distance over which it acts. 

Conservation of Energy Chapter 5 Section 3. What is Conservation? When something is conserved, it is said that it remains constant. The same holds true.

Energy and Conservation Physics Chapter 5-2 (p ) Chapter 5-3 (p )

Chapter 6 Work and Energy.

Kinetic Energy Chap 5 associated with motion, velocity.

Conservation of mechanical energy

Copyright © 2010 Pearson Education, Inc. Chapter 8 Potential Energy and Conservation of Energy.

Energy Conservation And Non-Conservative Forces. Conservation of Mechanical Energy Definition of mechanical energy: (8-6) Using this definition and considering.

6-4: Conservative and Nonconservative Forces The gravitational force has an interesting property that when an object is moved from one place to another,

Sect. 6-5: Conservative Forces. Conservative Force  The work done by that force depends only on initial & final conditions & not on path taken between.

2008 Physics 2111 Fundamentals of Physics Chapter 8 1 Fundamentals of Physics Chapter 8 Potential Energy & Conservation of Energy 1.Potential Energy 2.Path.

Conservation of Energy. Conservative Force One for which work done does not depend on the path taken only on initial and final positions Gravity and elastic.

Conservation of Energy IT’S THE LAW. Lifting a Ball When you lift a ball to a certain height you do work on it. When you lift a ball to a certain height.

Chapter 6 Work and Energy 6.1 – Work Work Formula & Units Positive & Negative Work 6.2 – Work-Energy Theorem & Kinetic Energy KE Formula & Units 6.3 –

5.3 The Conservation of Mechanical Energy THE PRINCIPLE OF CONSERVATION OF ENERGY The term conserved means constant.

Chapter 6 Work and Energy.

Potential Energy and Kinetic Energy Day 2

Last Thoughts on Work Work can be done by friction Friction always opposes motion so the work it does is usually negative. (exceptions are like conveyor.

Work - Work is calculated by multiplying the force applied by the distance the object moves while the force is being applied. W = Fs.

6-4: Conservative and Non-conservative Forces A force is a conservative force if the net work it does on a particle moving around any closed path, from.

Motion, Forces and Energy Lecture 7: Potential Energy & Conservation The name potential energy implies that the object in question has the capability of.

Chapter-6 Work and Energy Work Done by a Constant Force Work is done when a force F pushes a car through a displacement s. Work = Force X Displacement.

Forms of Energy.

ENERGY. A. Kinetic Energy (KE) 1. Energy in the form of motion. 2. Energy Depends On: a. Mass of the object. b. Velocity of the object.

Objectives: The students will be able to: Solve problems using the law of conservation of energy. Solve problems using the law of conservation of energy.

1. Work [W] = N*m = J Units: Work done by forces that oppose the direction of motion will be negative. Work and energy A. PositiveB. NegativeC. Zero Example:

Conservation of Mechanical Energy Mechanical Energy – The sum of Potential and Kinetic Energies ME=PE+KE The conservation of mechanical energy states that.

Copyright © 2010 Pearson Education, Inc. Lecture Outline Chapter 8 Physics, 4 th Edition James S. Walker.

Chapter 5.2. What do you think? What is meant when scientists say a quantity is conserved? Describe examples of quantities that are conserved. Are they.

Kinetic and Potential Energy UCR MESA. What is Energy? What does it mean if you have a lot of energy? For students it means you can run around, lift weights.

Examples: Mechanical Energy Conservation

WORK KINETIC ENERGY THEOREM. THE WORK ENERGY THEOREM Up to this point we have learned Kinematics and Newton's Laws. Let 's see what happens when we apply.

Conservation of Energy IT’S THE LAW. Lifting a Ball When you lift a ball to a certain height you do work on it. When you lift a ball to a certain height.

Chapter 5 Work and Energy. Mechanical Energy  Mechanical Energy is the energy that an object has due to its motion or its position.  Two kinds of mechanical.

Section 6-3 Gravitational Potential Energy. Warm-Up #1 A sailboat is moving at a constant velocity. Is work being done by a net external force acting.

Energy Review: Chapter 5 Section 1, Pages Kinetic Energy (KE) Energy of _________________________________________ If an object is ___________________________.

Unit 7 – Work, Energy, and Power CHAPTER 8 CONCEPTUAL PHYSICS BOOK.

Conservation of Energy (a.k.a Slacker Physics). Now, Really…Conservation of Energy In a system, energy can not be created or destroyed. Energy can change.

Dissipative Forces. Reality? In reality, non-conservative forces cannot be ignored: friction really does act Dissipative force is one that reduces the.

Kinetic Energy (E K ) Energy an object has due to its motion Potential Energy (E P ) Energy an object has due to its position/location Mechanical Energy.

Work-Energy Relationship Already understand that lifting an object will increase the object’s gravitational potential energy. W=ΔPE= mgΔh No friction.

PHYSICS 103: Lecture 12 Review of Example Problems Energy and Work Agenda for Today:

Work & Energy Review.

Potential Energy and Conservation of Energy

Lecture Outline Chapter 8 Physics, 4th Edition James S. Walker

Kinetic and Potential Energy

قطار التعرج مجلس أبوظبي للتعليم منطقة العين التعليمية

Conservation of energy

ماذا نعني بأن الطاقة كمية محفوظة؟!

Mechanical Energy.

Lecture Outline Chapter 8 Physics, 4th Edition James S. Walker

In this section you will:

The Nature of Energy Chapter 5.1

Potential Energy and Conservation of Energy

Presentation transcript:

Unit 5 - Work and Energy CHAPTER 8 CONCEPTUAL PHYSICS BOOK CHAPTER 6 PHYSICS BOOK

Part 2 CONSERVATION OF ENERGY AND POWER

Conservative vs. Nonconservative Forces  Conservative force – total Work on a closed path is zero. (ex: gravity)  Nonconservative force – total Work on a closed path is NOT zero. (ex: friction) Energy 3 -W+W -W Gravity- down Motion- up Friction – left Motion - right Friction - right Motion- left Gravity- down Motion- down

Conservation of Energy

Conservation of Mechanical Energy

Conceptual Example 1: Pendulum  Pendulum - Kinetic and Potential Energy Pendulum - Kinetic and Potential Energy  In the absence of air resistance and friction…  the pendulum would swing forever  example of conservation of mechanical energy  Potential → Kinetic → Potential and so on…  In reality, air resistance and friction cause mechanical energy loss, so the pendulum will eventually stop.

Conceptual Example 2: Roller Coaster  Roller Coaster - Kinetic and Potential Energy Roller Coaster - Kinetic and Potential Energy

With Non-Conservative Forces…

Conceptual Example 3: Downhill Skiing  Downhill Skiing - Kinetic and Potential Energy Downhill Skiing - Kinetic and Potential Energy  This animation neglects friction and air resistance until the bottom of the hill.  Friction is provided by the unpacked snow.  Mechanical energy loss (nonconservative force)  Negative work

Problem Solving Insights  Determine if non-conservative forces are included.  If yes: ME f = ME 0 + W nc (We won’t be solving this type)  If no: ME f = ME 0  Eliminate pieces that are zero before solving  Key words: starts from rest (KE 0 = 0), ends on the ground (PE f = 0), etc.

Example 1  A 2.00kg rock is released from rest from a height of 20.0 m. Ignore air resistance & determine the kinetic, potential, & mechanical energy at each of the following heights: 20.0 m, 12.0m, 0m (Round g to 10 m/s 2 for ease)

Example 1 - Answers HeightKEPEME 20.0 m 0 J2*10*20 = 400 J400 J 12.0 m = 160 J2*10*12 = 240 J400 J 0 m = 400 J2*10*0 = 0 J400 J Start Here Then Use This

Example 2 Find the potential energy, kinetic energy, mechanical energy, velocity, and height of the skater at the various locations below. 13 Energy max

Example 2 - Answers 14

Power

Power Example #1

Power Example #2

Power Example #3

Power Example #4