Circular Motion and Oscillations
Useful information
• Link to specification.
http://www.ocr.org.uk/images/81024specification.pdf
• Data, Formulae and relationships booklet.
http://www.ocr.org.uk/images/70733-datasheetdata-formulae-and-relationships-specimen.pdf
• Past papers, mark schemes and examiners
reports here.
http://www.ocr.org.uk/qualifications/as-a-levelgce-physics-a-h158-h558/
Useful Simulations (courtesy of PHET)
• Gravity and orbits.
http://phet.colorado.edu/en/simulation/gravit
y-and-orbits
• My Solar System.
http://phet.colorado.edu/en/simulation/mysolar-system
• Lady Bug Motion – 2D.
http://phet.colorado.edu/en/simulation/ladyb
ug-motion-2d
Circular Motion
Define the Radian
Angle Conversions
• How do you convert angles from degrees into
radians?
• How do you convert from radians into
degrees?
A force
perpendicular to the
velocity of an object
will make the object
describe a circular
path
Centripetal Force and Acceleration
•What is
meant by
centripetal
force?
•What is
meant by
centripetal
acceleration?
Key Equations
• What equation can be used to calculate the
tangential velocity of an object describing a
circle? Express in terms of r and T.
• What equation can be used to calculate the
centripetal acceleration of an object
describing a circle? Express in terms of a, v
and r.
Centripetal Force Equation
Gravitational Fields
How does a mass create a
gravitational field around it?
Gravitational Fields Lines
• What are the features of gravitational fields
lines?
• How can they be used to indicate the strength
of a gravitational field?
Radial and Uniform Fields
• What is the difference between a radial and a
uniform field?
What is the definition of gravitational
fields strength?
Newton’s Law of Gravitation
How could this law be put into words?
What does this equation calculate?
2
•g=-GM/r
• How can this equation be used to calculate
the mass of the Earth or similar object?
You need to be able to..........
• Analyse circular orbits in an inverse square law
field by relating the gravitational force to the
centripetal acceleration
What is the period of a circle?
Can you derive this equation?
4
p
2
3
T =(
)r
GM
2
What is Kepler’s third law?
What do each of these terms mean?
What is the definition of
geostationary satellite?
Can you give some uses of
geostationary satellites?
• Some hints here:
http://www.ehow.com/list_7218182_usesgeostationary-orbit-satellites.html
Have a look at this
• Real time satellite tracking 
http://www.n2yo.com/satellites/?c=34