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You have learnt about static electricity where charged particles (electrons) can move from one object into another giving objects an overall charge. In this unit1 you will learn about current electricity. This is when a continuous flow of charge can be created using a circuit made of conducting wires and an energy source.

The idea of the electric field, how it's useful, and explains how the electric field is defined.

• Determine the variables that affect how charged bodies interact.
• Predict how charged bodies will interact.
• Describe the strength and direction of the electric field around a charged body.
• Use free-body diagrams and vector addition to help explain the interactions.

The flicker of numbers on a handheld calculator, nerve impulses carrying signals of vision to the brain, an ultrasound device sending a signal to a computer screen, the brain sending a message for a baby to twitch its toes, an electric train pulling into a station, a hydroelectric plant sending energy to metropolitan and rural users—these and many other examples of electricity involve electric current, which is the movement of charge. Humanity has harnessed electricity, the basis of this technology, to improve our quality of life. 

There are many different processes and phenomena that emit electromagnetic radiation. Humans have taken advantage of many of these processes to develop technologies that use electromagnetic radiation.

When two objects interacting through a field change relative position, the energy stored in the field is changed.

• Explain the Conservation of Mechanical Energy concept using kinetic energy (KE) and gravitational potential energy (PE).
• Describe how the Energy Bar and Pie Charts relate to position and speed.
• Explain how changing the Skater Mass affects energy.
• Explain how changing the Track Friction affects energy.
• Predict position or estimate speed from Energy Bar and Pie Charts.
• Calculate speed or height at one position from information about a different position.
• Calculate KE and PE at one position from information about a different position.
• Design a skate park using the concepts of mechanical energy and energy conservation.

A force diagram is a useful tool to help us visualise forces acting on an object and gives us informa- tion about the object’s motion. We often use force diagrams when solving calculations involving the forces acting on an object.

By the end of this lesson you will be able to:

1. Define and explain what a force is
2. List and describe the main kinds of forces
3. Explain the effects of a force

In this unit you will learn:

• About the turning effect of forces
• Turning effects are called moments
• Understand that regular and irregular shaped objects have a centre of gravity
• An objects centre of gravity determines if it is in a stable, neutral, or unstable equilibrium