Students draw free body diagrams for objects with several forces, find the net force in each direction, and use Newton's first and second laws to say what the motion does (AC9S10U05, node 6).
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 10 min · Evaluate 3 min · Typical adds 3 min, Wider about 2 min
A concept tutorial for introducing or revising the idea. Set the width with ?width=minimum, typical (default) or wider. It follows Push the wall, and it pushes you? and pulls together the first and second laws. Integrating all three laws in problems (nodes 7 and 8) is a class task.
Not a hinge node, but students carry two errors into it: a moving object needs a net force forward, and forces the object exerts belong on its diagram. The plane prediction targets the first; the "what goes on it" question the second.
Board notes: the board draws forces from the object's centre (friction at the ground) with arrow length by size; large forces are capped in length, so read the labels. The plane's weight is given directly in newtons.
Working one direction at a time. When a student mixes vertical and horizontal forces in one sum, ask them to cover half the diagram with their hand and work the other half first.
| What you will see | A question to ask | The fix |
|---|---|---|
| A student adds weight to the horizontal forces. | Which way does weight point? | Down. Up–down forces balance separately from left–right ones. |
| A student draws the force the sled exerts on the rope. | Is that force acting on the sled? | No, on the rope. A free body diagram shows only forces on the object. |
| A student thinks the cruising plane needs more thrust than drag. | Is its speed changing? | No, so the net force is zero: thrust equals drag. |
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.
Stretch: A 60 kg person stands in a lift accelerating upwards at 1 m/s². How hard does the floor push on them? (Net force needed = 60 × 1 = 60 N up, so the floor pushes 60 × 9.8 + 60 = 648 N.)
Support: Give a diagram template: a box with four arrow stubs (up, down, left, right) to label, and a two-row table for each direction's net force.
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 "What forces act on it?". The idea: Multi-force analysis and free body diagrams: I can draw a free body diagram for an object with multiple forces and calculate net force, then apply F = ma to determine acceleration. What understanding looks like: - Draws a correctly labelled free body diagram for an object with at least three forces - Calculates net force and resulting acceleration from a free body diagram - Applies the result to explain a real-world scenario (e.g. vehicle safety, sport) Mistakes students often make here: - A student adds weight to the horizontal forces. - A student draws the force the sled exerts on the rope. - A student thinks the cruising plane needs more thrust than drag. 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 (Newton's Third Law — action-reaction pairs), 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 "What forces act on it?".
A 1000 kg car has 3000 N of driving force and 1000 N of drag. Find the net force and the acceleration.
2000 N forward; a = 2000 ÷ 1000 = 2 m/s².
Next: problems using all three laws (node 7) and real applications (node 8) are class tasks.
In class: force meters on a block dragged at steady speed; drawing free body diagrams for photos (a climber, a kite, a car braking).