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• Determine the variables that affect the strength and direction of the electric field for a static arrangement of charges.
• Investigate the variables that affect the strength of the electrostatic potential (voltage).
• Explain equipotential lines and compare them to the electric field lines.
• For an arrangement of static charges, predict the electric field lines. Verify the prediction using vector addition.

The amount of effort saved when using machines is called mechanical advantage (MA). Simple machines use mechanical advantage as a key property to their functionality, helping humans perform tasks that would require more force than a person could produce. We will use the lever as an example of a simple machine to illustrate the concept of mechanical advantage.

• Relate the electrostatic force magnitude to the charges and the distance between them
• Explain Newton's third law for electrostatic forces
• Use measurements to determine Coulomb’s constant
• Determine what makes a force attractive or repulsive

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.

• Predict, qualitatively, how an external force will affect the speed and direction of an object's motion.
• Explain the effects with the help of a free body diagram.
• Use free body diagrams to draw position, velocity, acceleration and force graphs and vice versa.
• Explain how the graphs relate to one another.
• Given a scenario or a graph, sketch all four graphs.

In this unit we will learn how these factors can affect the output of a simple machine. We will also learn about the difference between ideal mechanical advantage (IMA) and actual mechanical advantage (AMA), and how to apply your knowledge to calculate the efficiency of various simple machines.

In this lesson you will learn about:

• Simple machines
• Be able to identify different kinds of machines
• Identify classes of levers and pulleys
• Determine mechanical advantage of a lever and pulleys
• Understand and determine the advantage of an inclined plane
• Describe and determine the advantage of a screw jack
• Describe and determine the advantage of a wheel and axel
• Describe and determine the advantage of a hydraulic press

What are simple machines? Simple machines are tools that make work easier. They have few or no moving parts. These machines use energy to do work with one movement. They make our work easier by letting us use less mechanical effort to move an object.

This YouTube video investigates the structure and composition of the sun.

These four short online lessons cover the following:

• What is the sun?
• Interior of the sun
• Outer layers of the sun
• Surface features of the sun