§7.4 — Potential Energy
Not all forces behave the same. Some forces (gravity, springs, electric forces) are conservative: they return all the energy you invest if you…
§7.3 — Kinetic Energy
Kinetic energy is the energy an object possesses due to its motion. It is one of the most important quantities in physics because of the work–energy…
§7.2 — Variable Force Work
In the real world, forces rarely stay constant. A spring gets stiffer as it compresses. Gravity weakens with distance. Air resistance depends on…
Chapter 7 — Work and Energy
Work, kinetic energy, and the work-energy theorem — constant and variable forces, power, and force integration with worked examples.
6.9 — Q&A — Frequently asked questions for Chapter 6
1) Is “centripetal force” a new kind of force?
6.8 — Practice problems — 20 exercises for mastery
Twenty problems in three tiers. Answers at the end.
6.7 — Worked problems — advanced Newton’s-law applications
Seven worked problems exercising Chapter 6 tools.
6.6 — The fundamental forces of nature
All forces we see in nature — from falling apples to holding atoms together, from moving electrons to radioactive decay — trace back to four…
6.5 — Air drag and terminal velocity
An object moving through air experiences a force opposite its motion. Unlike surface friction (nearly constant), air drag is speed-dependent — and…
6.4 — Non-inertial frames and fictitious forces
Newton’s laws hold in inertial frames. In non-inertial frames (rotating or accelerating), an object accelerates with no apparent force — inconsistent…