Lesson 2-F5 Physics

8/18/2019 Lesson 2-F5 Physics

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B.Indah : No.15A, 17A, 21A & 41A, Jalan Indah 16/12, Taman Bukit Indah (Tel:

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Name : Teacher: Cheng Wui Leap

Subject : SPM Physics Class : F5 Physics

Chapter

:

Waves Lesson No :

!ate : "#$"$"#Topic : "% &nalysing 'e(lection o( Waves

"%) &nalysing 'e(raction o( Waves

Time : *%"5pm+#%"5pm

Notes:-

Damped Oscillations

"% What is ,amping-

!amping is the in the amplitu,e o( an oscillating system .hen its energy is ,raine, out

as heat energy% The amplitu,e o( an oscillating system .ill gra,ually ,ecrease an, become .hen

the oscillation stops

% What causes ,amping-

+/0ternal ,amping o( the system is the loss o( energy to .

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+ 1nternal ,amping is the loss o( energy ,ue to the in the

system%

)% & graph to sho. ,amping

*% /0ternal Force

To enable an oscillating system to go on continuously2 an (orce must be applie, to thesystem%

5% Force, oscillation

The e0ternal (orce energy to the system% Such a motion is calle, a (orce, oscillation

#% Natural (re3uency

The (re3uency o( a system .hich oscillates (reely the action o( an e0ternal (orce is

calle, the natural (re3uency%

7. Resonance

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'esonance occurs .hen a system is ma,e to oscillate at a (re3uency e3uivalent to its by

an e0ternal (orce% The resonating system oscillates at its 44444444444444444444444444444%

Experiment in Barton’s pendulum

"% The (re3uency o( a simple pen,ulum ,epen,s on the %

% 1n arton6s pen,ulum e0periment2 there are many pen,ulums tie, to the rope% T.o o( the pen,ulum are

o( the same length

)% When pen,ulum oscillates2 all the other pen,ulums are ____________________ to oscillate%

*% ut pen,ulum ! oscillates .ith the ____________________________ 2 ie2 pen,ulum ! resonates

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How does resonance occur in the two pendulum o e!ual len"th#

"% Pen,ulum an, pen,ulum ! are o( the ______________________.

% Fre3uency 7 Fre3uency !

)% There(ore2 pen,ulum causes pen,ulum ! to oscillate at its ______________________.

$ood eects o resonance

"% The tuner in a ra,io or television enables us to ___________________________ .e are

intereste,% The circuit in the tuner is is achieve,2 at the (re3uency

transmitte, by a particular station selecte,% 8ence a stron" electrical si"nal is pro,uce,%

% The o( music pro,uce, by musical instruments such as the trumpet an, (lute is

the result o( in the air%

Bad eects o resonance

%. & bri,ge can collapse .hen the o( its vibration increases as a result o(

______________________________ %

Tacoma Narrows Bridge

The original Tacoma Narrows Bridge roadway twisted and

vibrated violently under 40-mile-per-hour (64 km/h) winds

on the day of the collapse

Exercise

"% 9SPM6"$&$;


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=a> ?n,erline the correct ans.er in the brac@et to complete the sentence belo.%

!amping is a situation .hen the =amplitu,e2 .avelength> o( the oscillation ,ecreases%9" mar@<

=b> State one reason .hy ,amping occurs in the oscillating system%9" mar@<

=c> ase, on !iagram %$er,asar@an 'ajah %2

=i> state the perio, o( the oscillating system%9" mar@<

=ii> .hat is the (re3uency o( the oscillating system-9" mar@

=,> What .ill happen to the perio, o( the oscillating system .hen a heavier loa,is use,-9" mar@<

% 9;*$SPM6""


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=a> =i> Which pen,ulum .ill oscillate .ith the ma0imum amplitu,e-9" mar@<

=ii> ive one reason (or the ans.er in *=a>=i>% 9" mar@<

=iii> Name the phenomenon base, on the ans.er in *=a>=i>% 9" mar@<

=b> Calculate the perio, o( oscillation o( pen,ulum A% 9 mar@s<

=c> Pen,ulum A .ill stop oscillating a(ter a (e. minutes%

Dn !iagram *%2 s@etch the ,isplacement+time graph to sho. the ,amping

process% 9 mar@s<

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%.& Relection o 'a(es

Notes:-

Relection o wa(e

"% Dccurs .hen a .ave stri@es an obstacle%

% The .ave un,ergoes a change in ,irection o( propagation .hen it is re(lecte,%)% The value o( (re3uency =(>2 .avelength =E> an, spee, =v> remain the same a(ter re(lection%

)ncident wa(e : the .ave be(ore it stri@es the obstacleRelected wa(e: the .ave .hich has un,ergone a change in ,irection o( propagation

a(ter re(lection%

i 7 angle o( inci,ent the angle bet.een the ,irection o( propagation o( inci,ent .ave

an, the normal

r 7 angle o( re(lection the angle bet.een the ,irection o( propagation o( re(lecte, .ave

an, the normal%

*aw o Relection:

The angle o( inci,ence2 i is e3ual to the angle o( re(lection2 r%

Relection o plane water wa(es in a ripple tan+

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"% Set up a ripple tan@%

% S.itch on the motor to set the vibrating% 1ncrease the (re3uency o( the .aves by increasing the voltage po.er supply to the motor%

)% Dbserve the re(lecte, .ave by using a stroboscope%

!ra. a ,iagram to sho. re(lection o( .aves%

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Exercise

"% The ,iagram sho.s the stationary pattern o( plane .aves seen through a stroboscope .ith # slits

rotating at a (re3uency o( 5 8B%

What is

a the .avelength o( the .ater .ave- b the spee, o( the .ater .ave-

% & .ave is inci,ent on a plane re(lector P;%

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a What is the angle o( re(lection-

b Complete the ,iagram by ,ra.ing in the re(lecte, .ave%

)% 9SPM6*


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G% 9;)$SPM6I

Fre3uency

C Wavelength

! !irection o( .ave propagation

I% 9;)*$SPM6"

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Which comparison is correct bet.een the inci,ent soun, .ave an, the re(lecte, soun, .ave-

& The re(lecte, angle is bigger than the inci,ent angle

The spee, o( the re(lecte, .ave is the same as the spee, o( the inci,ent .ave

C The .avelength o( the re(lecte, .ave is less than the .avelength o( the inci,ent

.ave

! The (re3uency o( the re(lecte, .ave is lo.er than the (re3uency o( the inci,ent

.ave

"% 9;)$SPM6""


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∴v ∝ E v is ,irectly proportional to E

)% ?se the .or,s2 Kincrease62 ,ecrease6 or Kunchange,6

Characteristics Water .aves passes (rom ,eep

.ater to shallo. .ater

Spee,

Wavelength

Fre3uency

Characteristics Water .aves passes (rom shallo.

.ater to ,eep .ater

Spee,

Wavelength

Fre3uency

*% 8o. ,oes the ,irection o( .aves change .hen:

Water passing (rom the ,eep region to the shallo. region2 the .ater .ave is reracted toward the

normal%

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Water passing (rom the shallo. region to the ,eep region2 the .ater .ave is reracted awa3 (rom

the normal%

4se a ripple tan+

Draw a ra3 dia"ram to show reraction o wa(es.

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Lesson 2-F5 Physics

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