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Rogue Physicist.  Free resources for physics education © 2006-2016 Dorian Pascoe.  Email: dorian.pascoe@hotmail.co.uk

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A2 Unit G494

Chapter 11 - Out into Space
Content

Description
Momentum Use the ICT simulation here and follow the instructions here to investigate different collision scenarios and different types of collision.

 

Momentum Introduction to the concepts of momentum.

• calculating momentum as p=m∙v

• conservation of momentum using momentum before = momentum after

• solving simple problems using conservation of momentum (question sheet here)

Impulse to cause a change of momentum F∙t=mv-mu

• worked examples on board

You might find it useful to look at these example problems here.

Now try the simple problems here.

 
Momentum problems homework questions for homework Q150S - Impulse and Momentum in Collisions
Elastic collision calculator This little applet is very useful to check your answers for elastic collision problems.
Momentum and impulse experiment You are going to carry out an experiment to find the force exerted on a football when it is kicked.  This worksheet will guide you through the whole process.

We will use the equations of motion to deduce the forward velocity of the ball, and hence find the change in momentum.  A simple circuit involving capacitor discharge will allow us to measure the contact time between foot and football, and hence find the force.
Changes of momentum and mass flow rates Your teacher will explain how rockets work, and you will look at some simple examples of how the ejected gas leads to a change of momentum.

When you are happy you have understood, you will complete an analysis of a small toy helicopter hovering in order to find the mass flow rate and the velocity with which the air is propelled downwards by the helicopter's blades.

Now try this Question 11 from the G494 Jan 2009 exam paper, which covers the same ideas.
More homework questions

More homework questions Q180S - Jets and Rockets
Relevant exam questions G494 Jan 2010 Question 3

 

Models of the Solar System

Content

Description
Ptolemy's Geocentric model of the solar system Look at this page which has an interactive zoomable image of Ptolemy's model.  It is also worth looking at this website, which gives a little glimpse into the history of our models of the solar system.
Ptolemy's "Epicycles" idea This applet demonstrates Ptolemy's solution to the idea of "wandering stars" for both the inner and outer planets.
Wandering stars - retrograde motion This video was created using the open source "Cartes Du Ciel" (Skycharts) software.  It shows the path of the planets through the sky, including the apparent retrograde motion which can be observed.  You can download "Cartes Du Ciel" (Skycharts) for free from their website or SourceForge page.

Note: you'll probably want to view in fullscreen mode to see clearly!

 
Wandering stars - retrograde motion This applet illustrates how a heliocentric (sun centred) solar system can explain the apparent retrograde motion of planets.  It is also highly recommended that you look at the modellus file illustrating the same phenomenon.
Orbital Simulator

Set up systems of stars/planets/comets/moons etc and investigate the orbits.  Click here to load the applet.
Kepler's 1st law This applet illustrates the eccentricity of the orbits of all our planets, and a friendly neighbourhood comet.  Gives real-world data on perihelion and aphelion of each object - useful for orbital analysis problems.
Kepler's 2nd law This applet illustrates kepler's law of equal areas in equal times for elliptical orbits.  It doesn't look super-pretty, but gives some useful analytical tools and has real world data for astronomical objects.
Kepler's 2nd law This applet illustrates kepler's 2nd law too, (i.e. equal areas in equal times) but looks a bit prettier.
   
Circular Motion This document is a step-by-step derivation of the laws of circular motion.
Circular motion questions Here are some simple questions to test your understanding of circular motion!

Here are some questions about a theme-park ride (rather like "Vertigo" at Oakwood!) which will test your understanding of circular motion.

These are some more challenging questions.
Gravity as a uniform field These questions will test your understanding and extend your ideas about gravity as a uniform field.

You may also want to look at this page on the Institute of Physics TAP website.
How to measure G The experiment used to measure the universal gravitational constant "G" is usually credited to Cavendish, though in fact it was Charles Boys in Oxford who in fact measured G in or around 1893.  The experimental setup he used was similar to Cavendish's apparatus, but much more compact.  Your teacher will explain the history and how the experiment worked and show you these diagrams of the experimental apparatus.

You will also want to read the information on this document (Q60C) and answer the questions.
Gravity as a non-uniform field Here is an equation sheet with all the new formulae you have learned covering gravitational fields.
Gravity You will find some simple questions here to test your understanding of gravitational fields.
Changes in GPE and KE for orbits You are going to calculate the velocity of a satellite in various points around its orbit, by considering the energy changes as it moves through its orbital path.  Your teacher will guide you through an example of this, and may show you this simulation - which is nice for showing orbital eccentricity and variation in speed. 

When you are happy you understand, try these questions.

Teacher note: for Molniya orbit set semi-major axis to 26562km and eccentricity to 0.74

Incidentally, the Wikipedia page about Molniya orbits makes for interesting reading, as does this page from Astronautix.  Finally, as an aside, there is a table of data on this wikipedia page which is useful for devising questions about other orbits.
Chapter 11 Summary questions You will find some summary questions here to test your knowledge of the concepts covered in chapter 11.

 

 

 

 

Old resources

Content

Description
Momentum experiment This worksheet describes a simple experiment you can do on the airtrack to investigate inelastic collisions.  Thesepowerpoint slides show the practical setup, and help with the maths / analysis.
Momentum Applet This applet allows you to investigate the changes in momentum for both elastic and inelastic collisions of two trolleys.  Outcomes can be observed as the masses, directions of travel and velocities are varied.  Follow this worksheet and answer the questions to guide your investigation. 
Momentum starter questions Here are some quick starter questions for the subsequent lesson.