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PowerPoint Presentation– often through a disturbance in the

medium

pendulum

• Ex 1: find the period of a wave with a

frequency of 0.25 Hz

a period of 5 ms

s sHzf

with a frequency of 0.25 Hz

• Ex 2: find the angular velocity of an object

with a period of 5 ms

ω=2πf =2π(0.25Hz)

ω=2π/T =2π/0.005s

• Partner Purpose: to measure g

Procedure: refer to text, p. 5 but with the following changes: …

Observations:

0.10

0.15

0.20

0.25

0.30

0.35

• Since g

2 44

• Find g from your graph, then write a conclusion comparing your result to gravitational field g=9.8 m/s2

Simple Harmonic Motion

• Ex 3: sketch the graph of motion of the object from

example 1 if it started from 7cm above equilibrium position

x=7cos(1.5t)

v= -ωxosin(ωt)

v=-11sin(1.57t)

This gives:

v= 1.57 sqrt(7^2-2.7^2)

v=10.1cm s1

Start p. 107 #7-9

Bees can see in UV

• The mantis shrimp is a delightfully weird beastie. They’re multi-coloured, their genus and species names mean ‘mouth-feet’ and ‘genital-fingers’; they can move each eye independently, they see the world in 11 or 12 primary colours as opposed to our humble three, and now we find that this species can see a world invisible to the rest of us, said Professor White, of the University of Queensland.

• Mantis shrimps, dubbed “thumb splitters” by divers because of their vicious claws, have the most complex eyes in the animal kingdom, capable of seeing colors from the ultraviolet to the infrared, as well as detecting other subtle variations in light.

• They view the world in up to 12 primary colors- four times as many as humans - and can measure six different kinds of light polarization, Swiss and Australian researchers reported.

How damp is it?

How damp is it?

to friction, fluid resistance, etc.

The amount of damping can be classified as:

Start p. 107 #7-9

1. Waves were faster in the smaller slinky

2. Same

5. Only the disturbance travels

6. The waves reflected inverted (crest

reflected as a trough)

wavelength , we have:

v=f Ex 1: find the speed of a water wave with

wavelength 2.5 m and frequency 3 Hz

Don’t forget:

the bigger the better, and a microwave oven

to measure the speed of light

• Bring the chocolate for a Wednesday lab

day.

medium, we always find:

• The reflected wave will be:

– upright if the 2nd medium is less dense

– inverted if the 2nd medium is more dense

We can “see” wavelength as color

EM radiation

measured to be 14 cm

fc )102450(14.0 6

Ex 2: find the frequency of a 6.0 fm gamma

ray photon

– f=97.5 MHz

Total energy is a constant, depending on amplitude x

By conservation of energy, this also means:

Kinetic energy

Ex: find the kinetic energy for a 10 g mass on a spring

stretched 13 cm, when it is at a position of -3.5 cm

Potential energy can be found from other information,

e.g. Gravity or solved from total energy

Ex: find the potential energy for a spring stretched 13 cm,

when it is at a position of -3.5 cm

• Lab 8-4 p.160 Tuesday?

Answer Concluding Questions:

#1-2 p. 162 (reflection from parabola)

#1-3 p. 163 (diffraction)

• We find the waves are reflected with the same angle

Diffraction

• We get more diffraction with long wavelength, small opening

Refraction

• We can bend waves when they encounter a different medium

Start p. 125 #10-12

it resonates

and absorb those frequencies

found they pass through

space, they interfere

individual waves at each point

Wave Interference

the integer sum of the magnitudes.

• Draw the resultant of these two waves

interfering. Remember that the resultant

at each point is the integer sum of the

magnitudes.

Doppler effect with emitted light

• Blue shift: moving towards us

• Red shift: moving away

expanding!

• If the source is moving:

• Ex: find the frequency we hear for a 3000Hz sound from a car moving towards us at 25 m/s

• If the observer is moving:

• Ex: find the frequency we hear for a 250Hz sound if we run away at 13 m/s

Ex: find the frequency we hear for a 250Hz sound if we run away at 13

m/s

13330 250f

Hzf 240

Doppler formula

• For light:

• Ex: find the change in frequency we see for red light if a star moves away at 513,000 m/s

cf

f

Snell labs due Monday

• As the source moves faster through the medium, you can

see that the wavefronts start piling up in front of the

object, e.g. the “sound barrier.”

• Approaching the speed of sound the craft encounters the

sound waves piled on top of each other.

• Once the craft breaches the “sound barrier,” it leaves its

sound waves behind.

• The edges of these waves form a shock wave known as

the “sonic boom”

Labs due now

instantaneous

• Roemer (1676) made

the first successful

• Fizeau

• Foucault

• Michelson-Morley interferometer

believed light moved through a medium

called the æther.

rushing past the Earth

medium

pendulum

• Ex 1: find the period of a wave with a

frequency of 0.25 Hz

a period of 5 ms

s sHzf

with a frequency of 0.25 Hz

• Ex 2: find the angular velocity of an object

with a period of 5 ms

ω=2πf =2π(0.25Hz)

ω=2π/T =2π/0.005s

• Partner Purpose: to measure g

Procedure: refer to text, p. 5 but with the following changes: …

Observations:

0.10

0.15

0.20

0.25

0.30

0.35

• Since g

2 44

• Find g from your graph, then write a conclusion comparing your result to gravitational field g=9.8 m/s2

Simple Harmonic Motion

• Ex 3: sketch the graph of motion of the object from

example 1 if it started from 7cm above equilibrium position

x=7cos(1.5t)

v= -ωxosin(ωt)

v=-11sin(1.57t)

This gives:

v= 1.57 sqrt(7^2-2.7^2)

v=10.1cm s1

Start p. 107 #7-9

Bees can see in UV

• The mantis shrimp is a delightfully weird beastie. They’re multi-coloured, their genus and species names mean ‘mouth-feet’ and ‘genital-fingers’; they can move each eye independently, they see the world in 11 or 12 primary colours as opposed to our humble three, and now we find that this species can see a world invisible to the rest of us, said Professor White, of the University of Queensland.

• Mantis shrimps, dubbed “thumb splitters” by divers because of their vicious claws, have the most complex eyes in the animal kingdom, capable of seeing colors from the ultraviolet to the infrared, as well as detecting other subtle variations in light.

• They view the world in up to 12 primary colors- four times as many as humans - and can measure six different kinds of light polarization, Swiss and Australian researchers reported.

How damp is it?

How damp is it?

to friction, fluid resistance, etc.

The amount of damping can be classified as:

Start p. 107 #7-9

1. Waves were faster in the smaller slinky

2. Same

5. Only the disturbance travels

6. The waves reflected inverted (crest

reflected as a trough)

wavelength , we have:

v=f Ex 1: find the speed of a water wave with

wavelength 2.5 m and frequency 3 Hz

Don’t forget:

the bigger the better, and a microwave oven

to measure the speed of light

• Bring the chocolate for a Wednesday lab

day.

medium, we always find:

• The reflected wave will be:

– upright if the 2nd medium is less dense

– inverted if the 2nd medium is more dense

We can “see” wavelength as color

EM radiation

measured to be 14 cm

fc )102450(14.0 6

Ex 2: find the frequency of a 6.0 fm gamma

ray photon

– f=97.5 MHz

Total energy is a constant, depending on amplitude x

By conservation of energy, this also means:

Kinetic energy

Ex: find the kinetic energy for a 10 g mass on a spring

stretched 13 cm, when it is at a position of -3.5 cm

Potential energy can be found from other information,

e.g. Gravity or solved from total energy

Ex: find the potential energy for a spring stretched 13 cm,

when it is at a position of -3.5 cm

• Lab 8-4 p.160 Tuesday?

Answer Concluding Questions:

#1-2 p. 162 (reflection from parabola)

#1-3 p. 163 (diffraction)

• We find the waves are reflected with the same angle

Diffraction

• We get more diffraction with long wavelength, small opening

Refraction

• We can bend waves when they encounter a different medium

Start p. 125 #10-12

it resonates

and absorb those frequencies

found they pass through

space, they interfere

individual waves at each point

Wave Interference

the integer sum of the magnitudes.

• Draw the resultant of these two waves

interfering. Remember that the resultant

at each point is the integer sum of the

magnitudes.

Doppler effect with emitted light

• Blue shift: moving towards us

• Red shift: moving away

expanding!

• If the source is moving:

• Ex: find the frequency we hear for a 3000Hz sound from a car moving towards us at 25 m/s

• If the observer is moving:

• Ex: find the frequency we hear for a 250Hz sound if we run away at 13 m/s

Ex: find the frequency we hear for a 250Hz sound if we run away at 13

m/s

13330 250f

Hzf 240

Doppler formula

• For light:

• Ex: find the change in frequency we see for red light if a star moves away at 513,000 m/s

cf

f

Snell labs due Monday

• As the source moves faster through the medium, you can

see that the wavefronts start piling up in front of the

object, e.g. the “sound barrier.”

• Approaching the speed of sound the craft encounters the

sound waves piled on top of each other.

• Once the craft breaches the “sound barrier,” it leaves its

sound waves behind.

• The edges of these waves form a shock wave known as

the “sonic boom”

Labs due now

instantaneous

• Roemer (1676) made

the first successful

• Fizeau

• Foucault

• Michelson-Morley interferometer

believed light moved through a medium

called the æther.

rushing past the Earth