Unit Introduction

In the first three units of the first semester course, we utilized Newton's laws to analyze the motion of objects. Force and mass information were used to determine the acceleration of an object. Acceleration information was subsequently used to determine information about the velocity or displacement of an object after a given period of time. In this manner, Newton's laws serve as a useful model for analyzing motion and making predictions about the final state of an object's motion.

In this unit, an entirely different model will be used to analyze the motion of objects. Motion will be approached from the perspective of work and energy. The effect that work has upon the energy of an object (or system of objects) will be investigated; the resulting velocity and/or height of the object can then be predicted from energy information. In order to understand this work-energy approach to the analysis of motion, it is important to first have a solid understanding of a few basic terms. Thus, Lesson 1 of this unit will focus on the definitions and meanings of such terms as work, mechanical energy, potential energy, kinetic energy, and power.

Learning Objectives

Standard	I Can...	Task(s)
PI.4.1 Evaluate the translational kinetic, gravitational potential, and elastic potential energies in simple situations using the mathematical definitions of these quantities and mathematically relate the initial and final values of the translational kinetic, gravitational potential, and elastic potential energies in the absence of a net external force.	I can show mathematically how energy changes from one form to another.	7.2.1 Energy (Homework #1) 7.2.2 Work Energy Power (Quiz #1) 7.2.3 Conservation of Energy (Lab #1) 7.5.1 Review for Unit 7 Exam
PI.4.2 Identify the forms of energy present in a scenario and recognize that the potential energy associated with a system of objects and is not	I can define the different types of energy.	7.2.1 Energy (Homework #1) 7.2.2 Work Energy Power (Quiz #1) 7.2.3 Conservation of Energy (Lab #1) 7.5.1 Review for Unit 7 Exam
PI.4.3 Conceptually define “work” as the process of transferring of energy into or out of a system when an object is moved under the application of an external force and operationally define “work” as the area under a force vs. change in position curve.	I can define work in terms of forces and energy.	7.3.1 Energy (Homework #2) 7.3.2 Work Energy Power (Quiz #2) 7.3.3 Elastic Potential Energy (Lab #2) 7.5.1 Review for Unit 7 Exam
PI.4.4 For a force exerted in one or two dimensions, mathematically determine the amount of work done on a system by an unbalanced force over a change in position in one dimension.	I can mathematically determine the work done on an object.	7.3.1 Energy (Homework #2) 7.3.2 Work Energy Power (Quiz #2) 7.3.3 Elastic Potential Energy (Lab #2) 7.5.1 Review for Unit 7 Exam
PI.4.5 Understand and apply the principle of conservation of energy to determine the total mechanical energy stored in a closed system and mathematically show that the total mechanical energy of the system remains constant as long as no dissipative (i.e. non-conservative) forces are present.	I can explain why energy is always conserved.	7.4.1 Energy (Homework #3) 7.4.2 Power Lab (Lab #3) 7.5.1 Review for Unit 7 Exam
PI.4.6 Develop and apply pictorial, mathematical or graphical representations to qualitatively and quantitatively predict changes in the mechanical energy (e.g. translational kinetic, gravitational or elastic potential) of a system due to changes in position or speed of objects or non-conservative interactions within the system.	I can use my knowledge of the conservation of energy to determine an objects motion.	7.4.1 Energy (Homework #3) 7.4.2 Power Lab (Lab #3) 7.5.1 Review for Unit 7 Exam