General Physics 2023-2024 - Mechanical Energy | 5.2 General Physics

Chad provides a lesson on Mechanical Energy which is the sum of Kinetic Energy and Potential Energy and solves several mechanical energy physics problems. He begins by defining kinetic energy as the energy of motion and provides the kinetic energy formula (KE=1/2mv^2). He then provides definitions for conservative forces and nonconservative forces and explains that where there are conservative forces, potential energy is also possible. An object has potential energy simply when it as the potential to do work simply based upon its location in a system, and he introduces gravitational potential energy including its formula (PE=mgy or PE=mgh). Chad then introduces the Work-Energy Theorem which states that the net work done on an object will equal the change in kinetic energy of the object. It no net work is done, the kinetic energy remains constant and therefore so does the object's velocity. He then shows how the work done by nonconservative forces like friction and air resistance will equal the change in mechanical energy of an object. Nonconservative forces always oppose the motion of an object and therefore always perform negative work and thereby reduce the mechanical energy of an object. Finally, Chad presents the Conservation of Mechanical Energy which will hold true when only conservative forces are acting on an object. Chad finishes the lesson by solving several mechanical energy practice problems. One involves the calculation of kinetic energy and of the net work done on an object using the Work-Energy Theorem. Then Chad solves three problems involving the Conservation of Mechanical Energy. He shows how sometimes the same problems that can be solved with the Kinematics equations can be more easily solved with the Conservation of Mechanical Energy. He also solves an example on an inclined plane showing that the Conservation of Mechanical Energy still applies in such cases. This may seem surprising at first but shouldn't be as conservative forces are those in which the work done by the force in moving an object from one location to another is the same no matter the path. Finally, Chad concludes the lesson by solving the work done by friction (a nonconservative force) in an inclined plane problem with friction. He demonstrates that the work done by friction is equal to the loss of mechanical energy. 00:00 Lesson Introduction 00:49 Kinetic Energy and Potential Energy 02:39 Conservative Forces vs Nonconservative Forces 07:29 Work Energy Theorem 10:47 Work Done by Nonconservative Forces 12:06 Conservation of Mechanical Energy 13:24 Work Energy Theorem Problem 17:58 Conservation of Mechanical Energy Physics Problem #1 23:33 Conservation of Mechanical Energy Physics Problem #2 28:07 Conservation of Mechanical Energy on an Inclined Plane Problem 33:15 Work Done by Nonconservative Forces Problem Check out Chad's General Physics Master Course: https://www.chadsprep.com/physics-youtube #generalphysics #physicstutorial