Physics Unit 2 Exam Notes PDF

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Unit 2 Exam notes for physics...

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Physics Unit 2 Exa Exam m Notes Sheet of Mot Motion ion

Energy is the ability to do work (measured in Tension Materials which have been stretched, such as ropes or rubber, exert a force called tension. For ropes, tension is always towards the centre of the rope. To find the tension in a rope, calculate the upwards tension on the object. For a rope on a pulley, either object will do, as the tension force Kinetic Energy will be identical.

nversions (Handy) – Divide by 3.6 – Multiply by 3.6

Equations of Motion (Important)

Pulley Calculations Gravitational Potential Energy

Elastic Potential Energy Average accelerati n a

y

Average accelerati Average velocity:

Hooke’s Law k = spring constant (

, This is the same as for

Newton’s Laws Newton Newton’ss First Law

An object at rest or in motion will stay at rest or in motion until acted on by an outside force.

Newton Newton’ss Second L Law aw

The acceleration of a body is pro inversely proportional to the bod

Newton Newton’ss Third Law

For every action force, there i

Tension is th

ce:

to the net force applied and

opposite reaction force.

Energy Efficien

Law of Energy Conservation In any closed system, the amount of energy remains constant. Energy cannot be created nor destroy hange forms.

Momentum

Power

Often denoted by p,

Power is the rate of work

Momentum definition of force – Action-Reaction Pairs A pair of forces are action/reaction pairs if they are equal and opposite AND do not act on the same object. (Weight force/Normal force are NOT action/reaction pairs as they act on Impulse – the change in mom same object!)

Inclined Planes – Vec

rent direction

Finding Acceleration: (Note that BOTH masses required!) Finding Ten

ange of momentum

Rule for collisions – in any collision, the force on both objects is equal,

and so is the duration of time for which that force is applied.

Law of Conservation of Momentum

If the sum of external forces acting upon a system is zero, total momentum cannot change. Work

Measured in joules (J) Important – upward force does NO work! Work can be relative or net. Relative work is calculated on a specific source of force. Net work is calculated using the net force. Work = area under force/displacement graph.

Energy

, or force per unit displacement.

P is in Watts (W)

Collisions

Collisions are either elastic or inelastic . Elastic Collision – KE is preserved, i.e. Inelastic Collision – KE is not preserved, i.e.

Wave Interactions

Area of Study – Light

Speed of Light in Vacuum

Wave Reflections 1. A wave reflecting from f end of string undergoes phase reversal. (phase shift of ) 2. A wave reflecting from free end of string will not undergo phase reversal.

Waves

Waves tra

A wave may be a wave pulse or a continuous wave .

Superposition & Interference When 2 or more waves travel in moment of point, is the sum f individual wave, i.e.

m, the resulting wave, at any em associated with each

, frequency

Refraction – the bending of light due to a change in speed Refraction occurs when light enters a medium of different optical density . Refraction can be quantified

r second equation only: = index of medium carrying = index of medium carrying

Wave Pulse Continu Continuous ous Wave Waves may also be 1-D, 2-D, or 3-D 1-D wave – i.e. waves on a rope or spring 2-D wave – i.e. ripples on water surfaces 3-D wave – i.e. sphe al waves of nd wave has period ( .

The speed of light is dependent on the medium.

Angle of deviation (diff between

and ):

)

Rules of Refraction -

, wavelength ( ), and amplitude

-

When a light ray enters medium in which it travels m slowly (larger n), it is refracted towards the norma When a light ray enters medium in which it trave (smaller n ), it is refracted away from the normal.

r

Index of Refraction

After interactions, waves are able to continue unaffected!

Amplitude = max distance from mean position (unsigned!) Wavelength = length of one complete cycle Mean position = average position of one c Frequency = number of cycles completed Period = time taken to complete

Light Light may be modelled as a particle or a wave (and hence a ray), depending on the situation. (In VCE Physics 1/2, only wave model is considered) Colour → wavelength Brightness → amplitude

Critical Angle Applicable whe light goes from slower medium into faster medium. Critical angle, , is the minim gle ht is totally internally reflected.

Electromagnetic Radiatio

Law of Reflection

All EMR travels at c in v

I.e. angle of reflection is equal to the angle of incidence.

Wave Equation

R (only thing that differs is / )

For all EMR in vacuum: EMR composed of electric and magnetic fields oscillating perpendicular.

Dispersion Spreading out of white light into separate colours ∵ slightly different speeds in medium for different wavelengths. Note: in vacuum, all light travels at same speed regardless of λ

mportant nnot change – it dependent i dependent on th wave source If is constant, and is IV, then is DV.

arrying the wave.

Red (largest wavelength) → slowed least → refracted least Violet (smallest wavelength) → slowed most → refracted most All other colours between Red and Violet.

COLORS (because they can’t fit in elsewhere) Red + Green → yellow Red + Blue → magenta Green + Blue → cyan Red + Green + Blue → white

Polarisation Light waves may be modelled as rays. Rays may be convergent or divergent. Electroma Gamma R Infrared -

tic

m , UV , Microwaves -

sible S , TV -

trum Hz, Radio

Light has polarity, i.e. the EMR fields may have different angles. Polarised light has all EMR fields aligned. Polarising filters only allow the aligned components of light EMR to pass, hence blocking or reducing amplitude of light. Polarising glasses → reduce glare by blocking all light that is not aligned to the polarity of the sunglasses’ material....