Unit 04 · Forces & Motion
This unit gets things moving and asks why. You measure speed as distance over time, read motion off a distance–time graph, and learn what a force really does — a push or a pull that can start, stop, speed up, or turn an object. When the forces on something are balanced, its motion doesn’t change; when they’re unbalanced, it does. Newton’s three laws tie it all together. Mastery means you can measure motion at the bench and explain it with the forces behind it.
| Criterion | Not yet | Approaching | Mastered |
|---|---|---|---|
| Speed & distance–time | Confuses speed with distance or with time. | Measures speed but mixes up the units. | Measures distance and time, calculates speed, and reads it off a distance–time graph. |
| Forces: pushes & pulls | Cannot say what a force does. | Calls a force a push or pull but cannot spot one acting. | Identifies the forces on an object and describes the push or pull each one makes. |
| Balanced vs. unbalanced forces | Thinks a still object has no forces on it. | Defines balanced forces but cannot predict the motion. | Predicts whether motion changes from whether the forces on an object are balanced or unbalanced. |
| Newton's three laws | Cannot state a law of motion; thinks a moving thing needs a constant push to keep going. | Recites a law but cannot give a real example. | Explains each of Newton's three laws with a real example from the ramp or the bench. |
| Lab technique (motion on a ramp) | Releases the cart carelessly or mistimes the run. | Collects times but with inconsistent starts. | Rolls a cart down a ramp, times it cleanly, and links the measured motion to the force behind it. |
| Integration (cross-domain) | Treats the science as isolated facts; makes no cross-domain connection. | Names a link to history, reading, or writing but cannot defend why it matters. | Connects the unit to its anchor across History · Reading · Writing (plus chosen electives) and defends why the connection matters. |
“I rolled the cart down the ramp and timed it over a set distance to find its speed. It kept speeding up because gravity pulled it — an unbalanced force. On the flat table it slowed and stopped, not because it ‘ran out of push,’ but because friction pushed back against it.”
“The cart went faster because… it wanted to? It stopped on the table because it ran out of speed. Heavier carts fall faster, right?”
You demonstrate this unit through hands-on measurement — timing a cart on a ramp, reading its speed off your data, and measuring forces with a spring scale — plus short oral checks where you explain the motion aloud, not a multiple-choice test. A criterion counts as mastered only when you can both take the measurement and explain it with a force. Mastery is demonstrated, not awarded.
A 5-page clipboard packet — unit overview, key terms, the mastery rubric, anchor examples, and a score sheet you can print and grade against.