Year 7 Science · AC9S7U04

Forces, Motion, Gravity and Simple Machines

Investigate balanced and unbalanced forces, represent force magnitude and direction, relate changes in motion to mass and net force, and apply force ideas to gravity…

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Learning goalsSay it simply

Forces are pushes or pulls that can change an object's velocity. Students compare force magnitude and direction, investigate the effect of mass, measure forces in newtons, interpret force-arrow diagrams, explain Earth's gravity and examine how simple machines change the force needed for a task.

Central idea: motion changes when the forces on an object have a non-zero resultant or net force. Balanced forces give zero net force and therefore no acceleration; the object may be stationary or moving at constant velocity.
Key conceptTeach from the board

AC9S7U04: investigate and represent balanced and unbalanced forces, including gravitational force, acting on objects, and relate changes in an object's motion to its mass and the magnitude and direction of forces acting on it.

  • E1: different forces on familiar objects of same/different mass.
  • E2: balanced and unbalanced forces and changes in motion.
  • E3: force meters and force-arrow diagrams.
  • E4: Earth's gravitational force and mass.
  • E5: levers and pulleys changing required force.
  • E6: gravity in space.
  • E7: forces on boomerangs and airfoil design.
  • E8: simple-machine/force applications in First Peoples and Torres Strait Islander technologies.

Extension note: numerical use of F=ma, W=mg, kinetic-energy equations and formal mechanical-advantage equations strengthens problem solving but is not presented here as the only required Year 7 evidence for the descriptor.

Clean visual examplesOne-page board

Clean one-page examples

AC9S7U04 - Forces, Motion, Gravity and Simple Machines
Example 1

: different forces on familiar objects of same/different mass.

Example 2

: balanced and unbalanced forces and changes in motion.

Example 3

: force meters and force-arrow diagrams.

Example 4

: Earth's gravitational force and mass.

Curriculum examplesCopied content

AC9S7U04: investigate and represent balanced and unbalanced forces, including gravitational force, acting on objects, and relate changes in an object's motion to its mass and the magnitude and direction of forces acting on it.

  • E1: different forces on familiar objects of same/different mass.
  • E2: balanced and unbalanced forces and changes in motion.
  • E3: force meters and force-arrow diagrams.
  • E4: Earth's gravitational force and mass.
  • E5: levers and pulleys changing required force.
  • E6: gravity in space.
  • E7: forces on boomerangs and airfoil design.
  • E8: simple-machine/force applications in First Peoples and Torres Strait Islander technologies.

Extension note: numerical use of F=ma, W=mg, kinetic-energy equations and formal mechanical-advantage equations strengthens problem solving but is not presented here as the only required Year 7 evidence for the descriptor.

Questions and answersWith answers

AC9S7U04: investigate and represent balanced and unbalanced forces, including gravitational force, acting on objects, and relate changes in an object's motion to its mass and the magnitude and direction of forces acting on it.

  • E1: different forces on familiar objects of same/different mass.
  • E2: balanced and unbalanced forces and changes in motion.
  • E3: force meters and force-arrow diagrams.
  • E4: Earth's gravitational force and mass.
  • E5: levers and pulleys changing required force.
  • E6: gravity in space.
  • E7: forces on boomerangs and airfoil design.
  • E8: simple-machine/force applications in First Peoples and Torres Strait Islander technologies.

Extension note: numerical use of F=ma, W=mg, kinetic-energy equations and formal mechanical-advantage equations strengthens problem solving but is not presented here as the only required Year 7 evidence for the descriptor.

Practice and reviewReady for practice

AC9S7U04: investigate and represent balanced and unbalanced forces, including gravitational force, acting on objects, and relate changes in an object's motion to its mass and the magnitude and direction of forces acting on it.

  • E1: different forces on familiar objects of same/different mass.
  • E2: balanced and unbalanced forces and changes in motion.
  • E3: force meters and force-arrow diagrams.
  • E4: Earth's gravitational force and mass.
  • E5: levers and pulleys changing required force.
  • E6: gravity in space.
  • E7: forces on boomerangs and airfoil design.
  • E8: simple-machine/force applications in First Peoples and Torres Strait Islander technologies.

Extension note: numerical use of F=ma, W=mg, kinetic-energy equations and formal mechanical-advantage equations strengthens problem solving but is not presented here as the only required Year 7 evidence for the descriptor.

Curriculum alignmentStart here

Forces are pushes or pulls that can change an object's velocity. Students compare force magnitude and direction, investigate the effect of mass, measure forces in newtons, interpret force-arrow diagrams, explain Earth's gravity and examine how simple machines change the force needed for a task.

Central idea: motion changes when the forces on an object have a non-zero resultant or net force. Balanced forces give zero net force and therefore no acceleration; the object may be stationary or moving at constant velocity.

AC9S7U04: investigate and represent balanced and unbalanced forces, including gravitational force, acting on objects, and relate changes in an object's motion to its mass and the magnitude and direction of forces acting on it.

  • E1: different forces on familiar objects of same/different mass.
  • E2: balanced and unbalanced forces and changes in motion.
  • E3: force meters and force-arrow diagrams.
  • E4: Earth's gravitational force and mass.
  • E5: levers and pulleys changing required force.
  • E6: gravity in space.
  • E7: forces on boomerangs and airfoil design.
  • E8: simple-machine/force applications in First Peoples and Torres Strait Islander technologies.

Extension note: numerical use of F=ma, W=mg, kinetic-energy equations and formal mechanical-advantage equations strengthens problem solving but is not presented here as the only required Year 7 evidence for the descriptor.

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