Coaching Centre
Chapter 8: Forces Notes
Pushes and pulls, newtons and spring balances, contact and non-contact forces, balanced and unbalanced forces, force diagrams, friction and air resistance, car safety, gravity, mass and weight, magnets and magnetic fields, electromagnets, static electricity and lightning, and simple machines such as levers and the woomera.
Sections
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8A What forces are Mastered
Forces as pushes and pulls between two objects, the agent and the receiver, the six things a force can do, measuring forces in newtons with a spring balance, and contact and non-contact forces.
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8B Balanced and unbalanced forces Mastered
Adding forces to find the net force, balanced forces and staying still or moving at a steady speed, unbalanced forces and changes in motion, tug of war, and drawing force diagrams with arrows.
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8C Friction and air resistance Mastered
What causes friction, why it produces heat, when friction is useful and when it is a problem, the factors that affect friction, ways of reducing it (lubricants, rollers, bearings, air cushions, maglev), air resistance, drag and streamlining.
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8D Protection from forces Mastered
Why stopping suddenly causes big forces, cushioning by stopping over a longer distance, seat belts, airbags, crumple zones, helmets and other technologies that reduce the impact of forces in everyday life.
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8E Gravity, mass and weight Mastered
Gravity as a non-contact force acting through a field, the Earth's gravity pulling towards its centre, the difference between mass and weight, calculating weight on other planets, falling, air resistance and terminal velocity, floating in orbit, and buoyancy.
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8F Magnets and magnetic fields Mastered
Magnetic materials, kinds of magnets, north and south poles, attraction and repulsion, mapping magnetic fields with iron filings and compasses, the Earth as a giant magnet, compasses, the wandering magnetic poles and the aurora australis.
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8G Electromagnets Mastered
How an electric current makes a magnetic field, building an electromagnet, what makes an electromagnet stronger, soft iron cores, and uses of magnets and electromagnets including cranes, door locks, speakers, motors, maglev trains, recycling and MRI scanners.
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8H Static electricity Mastered
Electric charge, how objects become charged by rubbing as electrons move, attraction and repulsion between charges, attraction of neutral objects, insulators and conductors, static discharge, lightning and thunder, and uses and dangers of static electricity.
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8I Simple machines Mastered
How simple machines change the size or direction of a force, levers and the fulcrum, load and effort, the trade-off between force and distance, the woomera, wheels and axles, pulleys, gears and ramps.
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8J Forces review Mastered
A summary of the whole Forces chapter, key words, and a mixed test covering forces and newtons, balanced and unbalanced forces, friction, car safety, gravity, mass and weight, magnets, electromagnets, static electricity and simple machines.