Introductory Classical Mechanics Videos

Chapter 3: Energy & Work

This chapter examines quantities of energy, including kinetic energy and its change through work (force over distance). It introduces the organize of forces as conservative, dissipative, and constraint, with the work done by conservative forces quantified through potential energy. Finally, energy conservation and change of energy through dissipative work is illustrated through several worked examples.

Concept Videos

3.1C: Energy & Work

This concept video reviews the definitions of energy and work, highlighting the scalar nature of energy, its many forms beyond the kinetic energy of motion, the definition of work as change of kinetic energy as force over distance, the implications of the dot product when computing work, and finally the work-energy theorem.

3.2C: Conservative Forces and Potential Energy

This concept video examines conservative forces, such as weight, gravitation, or spring forces, in which energy of motion can be stored and extracted in the form of potential energy, and that the sum of kinetic and potential energy, or total mechanical energy, is conserved in the absence of dissipative forces. The video also presents a process of solving problems that involve energy conservation.

3.3C: Dissipative Forces and Energy Loss

This concept video examines non-conservative or dissipative forces, in which energy in the system is transformed into dissipative forms such as sound, heat, or vibration, and move away (or into) a system; a general approach to energy problems is introduced that includes dissipative forces.

3.4C: Energy Diagrams

This concept video illustrates the use of energy diagrams to explore the motion of a system, including speed, turn-around points, forbidden regions, and forces as a function of position, using spring force and atomic binding as examples; it also examines how a system evolves with energy dissipation.

3.5C: Power & Flux

This concept video introduces the physical quantities of power - the rate of change of energy with time - and flux - power per unit area, with examples drawn from biking, solar energy, and global power usage over time.

Problem Solving Videos

3.1P: Computing Work and Change in Kinetic Energy

This problem solving video illustrates approaches to computing kinetic energy and change and kinetic energy from work, in the latter case showing how to take into account the dot product between force and displacement vectors.

Notes

3.2P: Application of Work-Energy for Spring Motion

This problem solving video demonstrates how to use the work-energy theorem in solving for the motion of an object connected to a spring, showing how the spring potential is derived and illustrating the use of energy tables to solve for initial and final states of motion.

Notes

3.3P: Application of Work-Energy for Gravity

This problem solving video demonstrates how to use the work-energy theorem in cases of gravitation, with examples of achieving escape velocity from the Earth and Solar System, and how gravity assists work for spacecraft exploring the outer planets.

Notes

3.4P: Combining Energy, Forces, and Kinematics

This problem solving video demonstrates how to use work-energy in combination with Newton's Laws and kinematic equations for constant acceleration, using as the illustrative case the loop-de-loop of a rollercoaster.

Notes

3.5P: Energy Lost to Friction

This problem solving video illustrates how to use the work-energy theorem when the dissipative force of friction is involved, using energy tables and calculation of dissipative work in two worked examples.

Notes

Worksheets

Worksheet 3.1: Kinetic Energy and Work

This worksheet focuses on computing kinetic energies and work, then applying the work-energy theorem to compute velocity. Match to videos 3.1C and 3.1P-3.3P

Worksheet 3.2: Potential Energy & Energy Conservation

This worksheet focuses on the application of conservation of energy in the absence of dissipative forces. Topics include: computing potential energies, energy conservation and the energy table model, and energy diagrams. Match to videos 3.2C, 3.4C, and 3.2P-3.4P.

Worksheet 3.3: Dissipative Energy & Power

This worksheet examines how to include dissipative forces in work-energy. Topics include: computing dissipative work and calculating power. Match to videos 3.3C, 3.5C, and 3.5P.

Introductory Classical Mechanics Videos were created by Adam Burgasser and the UCSD Educational Technology Services (ETS)

This material is released under the CC-BY-NC-SA license, which allows re-users to distribute, remix, adapt, and build upon the material in any medium or format for noncommercial purposes only, and only so long as attribution is given to the creator. If you remix, adapt, or build upon the material, you must license the modified material under identical terms.

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