Physics Unit 3 - How Do Fields Explain Motion and Electricity?

Prerequisites

Students are advised to complete Physics Units 1 and 2 before undertaking Physics Unit 3. Mathematical Methods is strongly recommended.

Course Description

In this unit students use Newton’s laws to investigate motion in one and two dimensions. They explore the concept of the field as a model used by physicists to explain observations of motion of objects not in apparent contact. Students compare and contrast three fundamental fields – gravitational, magnetic and electric – and how they relate to one another. They consider the importance of the field to the motion of particles within the field. Students examine the production of electricity and its delivery to homes. They explore fields in relation to the transmission of electricity over large distances and in the design and operation of particle accelerators.

A student-designed practical investigation involving the generation of primary data and including one continuous, independent variable related to fields, motion or light is undertaken either in Unit 3 or Unit 4, or across both Units 3 and 4, and is assessed in Unit 4, Outcome 2. The design, analysis and findings of the investigation are presented in a scientific poster format.

Areas of Study

How do physicists explain motion in two dimensions?

In this area of study, students use Newton’s laws of motion to analyse linear motion, circular motion and projectile motion. Newton’s laws of motion give important insights into a range of motion both on Earth and beyond through the investigations of objects on land and in orbit. They explore the motion of objects under the influence of a gravitational field on the surface of Earth, close to Earth and above Earth. They explore the relationships between force, energy and mass.

How do things move without contact?

Field models are used to explain the behaviour of objects when there is no apparent contact. In this area of study, students examine the similarities and differences between three fields: gravitational, electric and magnetic. Students explore how positions in fields determine the potential energy of, and the force on, an object. They investigate how concepts related to field models can be applied to construct motors, maintain satellite orbits and to accelerate particles including in a synchrotron.

How are fields used in electricity generation?

The production, distribution and use of electricity has had a major impact on the way that humans live. In this area of study, students use empirical evidence and models of electric, magnetic and electromagnetic effects to explain how electricity is produced and delivered to homes. They explore the transformer as critical to the performance of electrical distribution systems in minimising power loss.

Assessment

Outcomes	Assessment Tasks	Marks Allocated
	(school-assessed coursework)
Outcome 1 Investigate motion and related energy transformations experimentally, and analyse motion using Newton’s laws of motion in one and two dimensions.	At least one task selected from the following (approximately 50 minutes or not exceeding 1000 words for each task):   application of physics concepts to explain a model, theory, device, design or innovation     analysis and evaluation of primary and/or secondary data, including data plotting, identified assumptions or data limitations, and conclusions problem-solving, applying physics concepts and skills to real-world contexts comparison and evaluation of two solutions to a problem, two explanations of a physics phenomenon or concept, or two methods and/or findings from practical activities.	40
Outcome 2 Analyse gravitational, electric and magnetic fields, and apply these to explain the operation of motors and particle accelerators, and the orbits of satellites	One task (which is different from the task/s selected for Outcomes 1 and 3) selected from the list in Outcome 1.	40
Outcome 3 Analyse and evaluate an electricity generation and distribution system.	One task (which is different from the task/s selected for Outcomes 1 and 2) selected from the list in Outcome 1.	40
Total Marks		120