🧭 Plot Summary
In everyday language, work means effort. In physics, it means something much more specific: a force moving something. Hold a heavy box still and your arms shake, but the box goes nowhere, so you’ve done no work on it. Lift that same box onto a shelf and you have.
You’ll build that definition from scratch, measure work in joules with a spring scale, and then use it to crack a puzzle: how can the distance a block slides before it stops tell you how fast it was moving? The answer is the work-energy theorem — the net work done on an object equals the change in its energy of motion.
What you will do in this activity
- Sort real situations into positive work, negative work, and zero work.
- Measure a pulling force and a distance, then calculate work in joules (J).
- Use the angle between a force and the motion to find how much of a pull actually does work.
- Slide a block to a stop and use friction’s work to find the energy it started with.
- Turn that energy into a starting speed using the work-energy theorem.
Why it matters
Everything else in Unit 4 — kinetic energy, potential energy, power, friction losses — is built on counting work. Get this foundation solid and the rest of the unit is the same bookkeeping with new labels.
✅ Self-Check Before You Roll On
Check off each item as you get there. These are not grades — they are your own signal.