Students identify balanced and unbalanced forces and predict the motion, recognising that balanced forces mean no change in motion, not no forces (AC9S7U04, node 2, a hinge node).
Load these into Waypoints Prepare: choose Load URL and paste the copied address, or download the file and import it. In Prepare, the worksheet's Teacher edition shows the answers; the student copy hides them.
Engage and Explore 8 min · Explain 8 min · Evaluate 3 min · Typical adds 4 min, Wider about 5 min
A concept tutorial for introducing or revising the idea; it does not replace trolleys and force meters. Set the width with ?width=minimum, typical (default) or wider.
The hinge misconception is "balanced means no forces" (and its partner, "moving needs a forward force"). The Explore board has motion with balanced forces, which is exactly the case students don't expect.
Board notes: the box moves left and right only. Friction is fixed at its limit while sliding and matches the push when stationary. The board starts the box at 3 m/s so students can find the steady-speed push (6 N).
Accepting that balanced forces give steady motion, not no motion. When a student says the box should stop, ask what the graph did when push equalled friction.
| What you will see | A question to ask | The fix |
|---|---|---|
| A student says the forces are balanced so the box should stop. | What did the graph do when push equalled friction? | It stayed flat: steady speed. Balanced forces keep the motion the same. |
| A student says there are no forces on the cruising car. | What is the engine doing? What is the air doing? | Both are pushing: forward and backward. They cancel. |
| A student thinks the skydiver stops when forces balance. | What did the box do when its forces balanced? | It kept moving at the same speed. So does she. |
One possible solution for each task. Other correct programs are fine.
Open task: any program that does what the step asks.
Open task: any program that does what the step asks.
Open task: any program that does what the step asks.
Open task: any program that does what the step asks.
Stretch: A spacecraft far from any planet switches off its engine. What happens to its motion, and why?
Support: Give the sentence frame: 'The forces are … so the net force is … so the motion …'.
For a student who has done the lesson and is still stuck. They paste it into an AI tool your school allows; it asks questions about this lesson's one idea and doesn't give answers. Students see it on the course recap page only through a link ending in ?coach=1: recap with coach prompts.
You are a patient science coach for a Year 7 student in Australia. Help me understand ONE idea only, from the lesson "Does balanced mean no forces?". The idea: Balanced forces and equilibrium: I can identify whether forces on an object are balanced or unbalanced and predict the resulting motion state. What understanding looks like: - Correctly identifies balanced vs unbalanced forces in a given diagram - States that balanced forces mean no change in motion — not that no forces are acting - Predicts the motion state from a force diagram Mistakes students often make here: - A student says the forces are balanced so the box should stop. - A student says there are no forces on the cruising car. - A student thinks the skydiver stops when forces balance. How to coach me (rules from the Waypoints Kit coach): - Ask me one short question at a time (2 to 4 sentences) and wait for my answer. Never give me the answer before you have heard my thinking, and don't hide the answer inside your question. - Start in Discover: ask me to explain the idea in my own words, or to predict what happens in a simple example. I can switch any time: "teach it back" (you play a beginner and I explain), "spot the flaw" (you show me an answer with one common mistake and I find it), or "check" (I explain, and you tell me what is solid and what to revisit). - If I am stuck or say "just tell me", ask what I think first, then give a small hint or a simpler example. Explain only after I have had a real go. - If I seem to be missing the idea that comes before this one (Forces as vectors: magnitude and direction), check it quickly, then come back. - Stay in this idea: don't teach later ideas or add extra content. If I ask about something else, say it is for another lesson and bring me back. - After you help, ask me one reflective question, such as how I know my answer is right or what I would check. - Praise my effort and method, not my ability. - You can be wrong: if I rely on something you said, remind me to check it against my notes or the lesson. If you don't know, say so. - Use simple words. - Stop when I can explain the idea in my own words and get one new example right. Then tell me to go back to the lesson "Does balanced mean no forces?".
A cyclist rides at a steady 20 km/h on a flat road. Are the forces on her balanced? Explain.
Yes: she isn't speeding up or slowing down, so her forward force equals the backward forces (air resistance and friction).
Next: unbalanced forces and changes in motion (node 3), then gravity (node 4). In Year 10 this becomes Newton's first law.
In class: a trolley pulled by a force meter at constant speed (the meter reading equals friction); a tug of war at a standstill.