**A2 Physics 6.1 Periodic motion**

Lesson 1: Circular Motion and A2 Introduction

A2 Introduction

http://filestore.aqa.org.uk/resources/physics/specifications/AQA-7407-7408-SP-2015-V1-2.PDF

Required Practicals

Circular Motion

Why is it possible to swing a bucket of water over your head without getting wet?

Circular Motion

Motion in a circular path at constant speed implies there is

an acceleration and requires a centripetal force.

Task:

Sketch the bucket and string scenario.

On the bucket draw the forces acting on it.

Note down:

What direction is the resultant force?

What direction is the acceleration?

Ext:

What other examples are there of circular motion?

We need to use a different measurement for measuring angles when describing circular motion:

The Radian

The Radian

One radian is the angle subtended at the centre of a circle by an arc of length equal to the radius of the circle

Angle in radians = arc length / radius

What is the angle in radians for one complete revolution (Hint circumference = 2πr

Task

1) In your own words define radians

2) An angle subtends an arc length of twice the radius. What is the angle in radians?

3) An angle subtends half a circle what is the angle in radians?

Ext: Write an equation to convert radians to degrees.

For a complete circle (360 degrees) the arc length is the circumference of the circle (2πr).

Dividing this by the radius (r) gives 2π . So there are 2π radians in a complete circle

Using the fact that 360 degrees = 2π radians

Derive the number of radians for

1) 45 degrees

2) 90 degrees

3) 190 degrees

Why might radians be a better unit than degrees?

Derive the number of degrees for

1) 3π radians

2) 4 radians

3) 0.5π radians

Heads up!

Lesson 3: Damping Experiment

What is damping?

Read the information about the skyscraper Taipei 101.

Describe what you think damping is with reference to energy

How is Taipei 101 designed for damping?

Damping

Damping experiment

Hypothesis: As the surface area of a pendulum increases the damping force due to air resistance increases.

Aim: To investigate this hypothesis

Task 1: In groups of 3 discuss how this hypothesis could be investigated in the lab

Task 2: Write a requisition for equipment needed

Task 3: Draw a table to record your results

Experiment Preparation

1) Identify:

A possible source of systemic error

The absolute uncertainty of your instruments

The percentage uncertainty of your results

The total percentage uncertainty of your results

2) Ambassadors:

Send 1 person to another group, ambassadors explain your method and compare to other groups.

Make notes on damping using the printout

Copy the graph and distinguish between light damping, heavy damping and critical damping

Induction Lesson:

**Resonance**

What is physics like?

Course:

AQA

Requirements:

2B's in GCSE Science

Required for:

Physics degrees

Mechanical engineering

Beneficial for:

Mathematical degrees

Medicine

Buisness/accounting degrees

Example topic: Resonance A2

What is resonance?

What was driving the oscillation?

Why was this a problem?

What was the solution?

Resonance is when the amplitude of an oscillation increases exponentially.

Natural Frequency

All objects which can oscillate have a natural frequency of vibration. This is independent of amplitude.

Natural frequency is the frequency at which a system tends to oscillate in the absence of any driving or damping force

1) Describe three situations where resonance occurs

2) Anticipate one method of controlling resonance

Ext: Does resonance show the conservation of energy being refuted?

Year 12 advice from this year

1) A lot of the GCSE is irrelevant

2) You cannot revise at the last minute, start immediately

3) Keep your folder organised

4) The specification is very new

5) Practicals have to be taken seriously now

6) You will find it difficult without AS maths (A2 will be nearly impossible)

7) Pace is fast

8) Stay on top of homework!

Exams and scheme of work:

http://filestore.aqa.org.uk/resources/physics/specifications/AQA-7407-7408-SP-2015-V1-2.PDF