Students apply F = ma to find force, mass or acceleration with units, use the net force, and explain how changing force or mass changes acceleration (AC9S10U05, node 4, 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 9 min · Practise 4 min · Evaluate 3 min · Typical adds 4 min, Wider about 2 min
A concept tutorial for introducing or revising the idea; it does not replace a trolley and hanging-mass practical. Set the width with ?width=minimum, typical (default) or wider.
The hinge risks are using the applied force instead of the net force, and dropping units or direction. The net-force question in Explain targets the first.
Board notes: the acceleration reading (under the board) is the net force divided by the mass, and shows before Play, so students can tune the push without running it. No friction on this board.
Using the net force, not the push, in F = ma. When a student uses the push, ask whether anything is pushing back.
| What you will see | A question to ask | The fix |
|---|---|---|
| A student uses the push instead of the net force. | Is anything pushing back? | Subtract opposing forces first: F in F = ma is the net force. |
| A student confuses mass and weight in F = ma. | Which is in kilograms? | Mass (kg) goes in F = ma. Weight is a force (N). |
| A student thinks doubling mass halves the force needed. | For the same acceleration, what did you need for 8 kg compared with 4 kg? | Twice the force. Same force on double the mass gives half the acceleration. |
Stretch: Rockets lose mass as they burn fuel. With the same thrust, what happens to their acceleration during the launch?
Support: Give the formula triangle (F at the top, m and a below) with one worked example of each rearrangement.
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 10 student in Australia. Help me understand ONE idea only, from the lesson "How hard do you need to push?". The idea: Newton's Second Law — F = ma: I can apply F = ma to calculate force, mass or acceleration in single-force scenarios and explain qualitatively how changing mass or force affects acceleration. What understanding looks like: - Correctly applies F = ma to solve for force, mass or acceleration in a single-force scenario - Uses correct units (N, kg, m/s²) and maintains direction consistency - Explains qualitatively how doubling force or mass affects acceleration Mistakes students often make here: - A student uses the push instead of the net force. - A student confuses mass and weight in F = ma. - A student thinks doubling mass halves the force needed. 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 (Acceleration as a defined vector quantity), 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 "How hard do you need to push?".
What acceleration does a net force of 30 N give a 6 kg trolley?
a = F ÷ m = 30 ÷ 6 = 5 m/s², in the direction of the net force.
Next: Newton's third law (node 5), then free body diagrams with several forces (node 6) and quantitative problems (node 7).
In class: a trolley pulled by hanging masses (move masses from the trolley to the hanger to keep total mass constant), with light gates or a motion sensor.