Work and Energy Chapter 5. Work Definition of Work  What do you think?  Work is done on an object when a force causes a displacement of the object.

Slides:



Advertisements
Similar presentations
Chapter 5: Work and Energy
Advertisements

Work Chapter 5 Section 1.
Chapter 5 – WORK and ENERGY
Chapter 10: Work, Energy, and Simple Machines
Work and Energy  Work: The word looks the same, it spells the same but has different meaning in physics from the way it is normally used in the everyday.
Section 5-1. Work – Section 5-1 Definition of Work Ordinary Definition : To us, WORK means to do something that takes physical or mental effort. ◦ Ex:
Work December 2, Many of the terms encountered in physics have meanings similar to their meanings in everyday life. In its everyday sense, the term.
Chapter 5 Work and Energy
Chapter 5 Work and Energy
Physics 111: Mechanics Lecture 6 Wenda Cao NJIT Physics Department.
Chapter work.
Work and Energy © 2014 Pearson Education, Inc..
Work and Energy.
WORK AND ENERGY 1. Work Work as you know it means to do something that takes physical or mental effort But in physics is has a very different meaning.
Work Page 168.
Physics Lecture 31 Instructor: John H. Hamilton. Lecture overview This week, Work and Energy Work – What work is – How is work calculated Power – Calculating.
Energy, Work and Simple Machines
Work and Energy Chapter 5. Work Definition of Work  What do you think?  Work is done on an object when a force causes a displacement of the object.
Work has a specific definition in physics. Work is done anytime a force is applied through a distance.
Work, Kinetic Energy, and Power. v f 2 = v i 2 + 2ad and F = ma v f 2 -v i 2 = 2ad and F/m = a v f 2 -v i 2 = 2(F/m)d Fd = ½ mv f 2 – ½ mv i 2 Fd = Work.
Chapter 6 - Work and Kinetic Energy Learning Goals What it means for a force to do work on a body, and how to calculate the amount of work done. The definition.
Chapter 6 Work and Energy. Units of Chapter 6 Work Done by a Constant Force Work Done by a Varying Force Kinetic Energy, and the Work-Energy Principle.
|||| 6.4 WORK Integral & Applications of Integration Dicky Dermawan
Work AP style. Energy Energy: the currency of the universe. Everything has to be “paid for” with energy. Energy can’t be created or destroyed, but it.
Work Chapter 8.1 Go to Go to “Lesson 1” and go over the two “Work” topics.
Work and energy. Objectives 1.Recognize the difference between the scientific and the ordinary definitions of work. 2.Define work, relating it to force.
Chapter 5: Work, Power, and Energy Chapter 5-1 (p ) Physics.
Work and EnergySection 1 © Houghton Mifflin Harcourt Publishing Company Preview Section 1 WorkWork Section 2 EnergyEnergy Section 3 Conservation of EnergyConservation.
Work and Energy Chapter 5 pg Chapter 12 pg
Work and EnergySection 1 Unit 3 Lesson 1: Work Goals: Recognize the difference between the scientific and ordinary definitions of work. Define work by.
Work, Energy, and Power Chapter 5
November 4 th 2009 Objectives SWBAT Define work SWBAT Calculate net work. SWBAT Calculate Kinetic Energy for an object Catalyst What is the definition.
Work, Power, & Efficiency
Work. Definition Work is done on an object by a constant force moving the object through a distance It is the product of the displacement and the component.
Energy Introduction Lesson 1. Definition of energy When energy is transferred from one form to another it may be transferred by doing work. For example,
Work. Definition Work is done on an object by a constant force moving the object through a distance It is the product of the displacement and the component.
Work and EnergySection 1 Preview Section 1 WorkWork Section 2 EnergyEnergy Section 3 Conservation of EnergyConservation of Energy Section 4 PowerPower.
Chapter 5 Work and Energy.
Work Physics 11. Comprehension Check 1.What is the impulse given to a golf ball of mass 45.9g if it starts at rest and attains a final velocity of 35m/s?
Chapter 8A. Work A PowerPoint Presentation by Paul E. Tippens, Professor of Physics Southern Polytechnic State University A PowerPoint Presentation by.
Work F d . Work is a Bridge to Energy Land of Forces & Motion Land of Energy WORK Conceptual Bridge PE = mgh KE = ½mv 2 F resistance F forward F ground-on-car.
Energy, Work and Power. Energy Energy: the currency of the universe. Just like money, it comes in many forms! Everything that is accomplished has to be.
Chapter 6 Work & Energy. 6.1 Work Done By A Constant Force When a force acts upon an object to cause a displacement of the object, it is said that work.
Work and Energy. Work Physics definition of Work: Work : is the product of the magnitudes of the component of force along the direction of displacement.
Physics 218 Alexei Safonov Lecture 10: From Work to Energy.
© 2013 Pearson Education, Inc. Chapter 10 Work Chapter Goal: To develop a more complete understanding of energy and its conservation. Slide 11-2.
Hand in labs. Get into groups of 2-3 Discuss the following question: Which requires more work? Holding a heavy chair at arm length for a few minutes Carrying.
Aim: How can we apply work- energy to motion problems? Do Now: In your own words, what does energy mean to you? In your own words, what does energy mean.
Chapter 7.1 and 7.7 Work and Power What is energy? Energy is defined as the ability to do work.Energy is defined as the ability to do work. But in some.
Work and Energy.  The concept of work has different meanings in everyday use.  In physics, Work is used to describe what is accomplished by the action.
Work, Power and Kinetic Energy. Work Work is a force acting through a distance In order for work to be done: –The object the force is applied to must.
Work and Power. Work Let’s look at some examples of moving a book where “work” is being done and “work” is not being done on the book. Move the book from.
WORK.
Recognize the difference between the scientific and ordinary definitions of work. Define work by relating it to force and displacement. Identify where.
Work and Energy Work.
Chapter 7 Work and Energy
WORK.
Unit 5 Work, Power, and Energy.
Energy Part 4: Work.
Chapter 7 Work and Energy
Work and Energy.
Chapter 7 Work and Energy
3.2.1 Introduction to Work & Energy
Chapter 10 Work and Energy
Chapter 5 Pgs
Work and Energy.
Work is measured in Joules (J)
Work and Energy Chapter 5 Physics.
Warm-up Describe a situation that requires work..
Work.
Presentation transcript:

Work and Energy Chapter 5

Work

Definition of Work  What do you think?  Work is done on an object when a force causes a displacement of the object.  Work changes the amount of energy in an object!

Pushing Your Car  Imagine your car has ran out of gas.  You have to push.  If you push with a constant horizontal force then the work done is equal to the magnitude of the force times the magnitude of displacement of the car.  W = F*Δx

Is Work Done When...  If you hold a chair at arms length is work done on the chair?  NOOOOOOOOOOOOOOOOOOO!  Work is not done on an object unless the object is moved with the action of a force.  The muscles in your tired arms are doing work inside your body, but not on the chair.

Work WWWWork is done only when components of a force are parallel to a displacement. IIIImagine pushing a crate along the ground. IIIIf all your force is horizontal, all your effort moves the crate. IIIIf your force is at an angle, only the horizontal component of your force moves the crate and contributes to work.

Push the table!  Push the table you are sitting at (or chair depending)  1 st push it by applying a force at a downward angle.  Next push it back by applying a force that is completely horizontal.  How did the forces compare?

Example:  While climbing a horse to go horseback riding, you are applying a force that will pull you up on top of the horse. You are doing work to climb up because the direction of the force is parallel to the direction of the motion.

Work YYYYour turn! Take two minutes to come up with an example of work that you have experienced at some point this week. WWWWrite it down in your lab book, then share your idea with a partner. CCCCheck to see if each others example is in fact an example of work.

Crate

Work  If θ = 0° then cos 0° = 1 and W = Fd.  If θ = 90° then cos 90° = 0 and W = 0.  So no work is done on the crate when force is applied downward at a 90° angle.  Work = F*Δx θ  If many forces are acting on an object we can find the net work done.  Work net = F net *Δx*cos θ

Work Dimensions WWWWork has the dimensions of force x length. WWWWhich is N x m (Newton’s x meters) AAAAlso known as Joules (J) WWWWhat is a Joule? 1111 J is about the amount of work it take to life an apple from your waist to the top of your head.

Example  Gen:  How much work is done on a vacuum cleaner pulled 3.0 m by a force of 50.0 N?  Adv:  at an angle of 30.0° above the horizontal?

Solution  Gen: Work=F*Δx  Plug and chug  W = (50 N)*(3.0 m)  W= 150 J  Adv: Work=F*Δx *cos θ  Plug and chug  W = (50.0 N)(3.0 m)(cos 30.0°)  W = 130 J

Your Turn  Gen: A man pulls a horse with a constant net horizontal force of N and causes the horse to move through the stables. How much work is done if the horse moves a distance of m?  Adv: In reality, the man is pulling the horse at a downward angle of 25° with a constant force of N, which cause the horse to move through the stables. How much work is done if the horse moves a distance of 13.0 m?

The Sign of Work  The sign of work is important.  Positive or negative.  Work is positive when the force is in the same direction as the displacement.  Work is negative when the force is in the direction opposite of the displacement.

Example:  When throwing a lacrosse ball, the ball would be experiencing a positive amount of work.  When catching a lacrosse ball, the ball would be experiencing a negative amount of work.

Your turn:  Write in your lab book an example of positive/negative work?  Share your idea with your neighbor.

Graphing!  Work can also be solved utilizing graphing methods.

In this image, where is the work?

W = F * Δx so…….  Work is the are under the curve in a Force vs. Displacement graph.

What are the different types of energy in the universe?

Take a minute!  Do a quick google search and try to identify all of the different types of energy out there!  Create a list with a brief description in your lab book.