83
A. Gaya Memengaruhi
Gerak Benda
B. Penerapan Hukum Newton
Dinamika Gerak
6D:2 6?562D: 82B:C A6=2B: 22? 6A6B46A2D =2B:?H2 ,6D6=296=6G2D:82B:C5:222?6A6B=232D=2B:?H2 A229
H2?86A6B46A2D52?6A6B=232D86B2A6=2B:D6BC63ED :,?52D6=296A6=2;2B:86B252?9EE9EE6GD?
D6?D2?886B2 2=269:5EA2?C692B:92B:?52D:52A6B?29D6B=6A2C 52B:86B2 ,6B2?82?236B=2B:6?86;2B3=2?5236B;2=2?6C6=29
52?3EC36B86B26?:?882=2?D6B:?2=6BEA22?3636B2A24?D9 86B2 A229C636?2B?H2H2?86?H63232?36?5236B86B2
2D:=2936?5236?5236B86B25:C6:D2B?52:C2=?H23:= C6A652DB52?36?52H2?836B2HE?A252C6ED2CD2=: 282:2?229
:C:26?;6=2C2?D6B;25:?H286B2?5222?6292:?H2C6D6=29 6A6=2;2B:323:?:
menerapkan Hukum Newton sebagai prinsip dasar dinamika untuk gerak lurus, gerak vertikal, dan gerak melingkar beraturan.
Setelah mempelajari bab ini, Anda harus mampu:
menerapkan konsep dan prinsip dasar kinematika dan dinamika benda titik.
Hasil yang harus Anda capai:
Setelah melewati garis finish, pelari memperlambat laju larinya.
Bab
5
Sumber:
Bergulir dan Mengalir,2004
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Mudah dan Aktif Belajar Fisika untuk Kelas X
A. Gaya Memengaruhi Gerak Benda
25223?52D6=296A6=2;2B:86B2CE2DE36?52D2?A26=:92D 2A2H2?86?H63232?86B236?52D6BC63ED ,E3323:?:22?63292C
A6?H632352B:86B2 252AB:?C:A?H2H2?866?82BE9:86B2CE2DE36?52252=2982H2 2
=2:=E :C:282H26BEA22??C6AH2?8C2?82DA6?D:?8 523636B2A2 24282H2H2?8C6B:?85:;EA2::C2=?H282H236B2D82H2DD52?82H2A682C
E3E?82?2?D2B286B236?5256?82?82H2H2?866?82BE9:36?52 D6BC63ED5:3292C5:52=29EE9EE6GD?D6?D2?886B2
1. Hukum I Newton
,6D:2A 36?52 6:=:: 646?56BE?82? E?DE 6A6BD292?2? 65E5E2??H2 ,63E29 36?52 52=2 62522? 5:2 6:=::
646?56BE?82? E?DE D6D2A 5:2 ,632=:?H2 36?52 52=2 62522? 36B86B26:=::646?56BE?82?E?DED6D2A36B86B2 ,:72DC6A6BD::?:
5:?222?2D2E ,:72D6=6322?52A2D?52B2C22?6D:2?5236B2525: 52=2
6?52B22?H2?8C652?836B86B26E5:2?C642B2D:32D:326?52B22?D6BC63ED 5:B6C69:?882?52D6B5B?8656A2? 2=:?:D6B;25:2B6?2C636=E
A6?86B62??5252=262522?36B86B2656A2?56?82?646A2D2?C22 56?82?6?52B22?C69:?8826D:25:B6?52D6B5B?8656A2?2B6?2
?526:=::646?56BE?82?E?DED6D2A36B86B2 A2H2?822??52 2=2:6D:26?52B22?E=2:36B86B2632=:6?82A256::2?
,:72D6=6322?36?525:E?82A2?=690 41-,C63282: EE6GD? EE6GD?6?H2D22?329G2
...
Aktivitas Fisika 5.1
Kelembaman
Tujuan Percobaan Mengamati sifat kelembaman benda
Alat-Alat Percobaan 1.
Selembar kertas 2.
Gelas 3.
Uang logam
Langkah-Langkah Percobaan 1.
Letakkan selembar kertas di permukaan sebuah gelas, kemudian di atas kertas tersebut letakkan sebuah uang logam koin seperti pada Gambar 5.1.
2. Tariklah kertas dengan cara dihentakkan. Di manakah koin itu jatuh?
3. Tariklah kertas secara perlahan-lahan. Apa yang terjadi dengan koin tersebut?
4. Apa yang Anda simpulkan dari kegiatan ini?
2+++. -,0., + , 0- 0- 21 +22 1 ,
Tes Kompetensi Awal
A2H2?8?526D29E:D6?D2?882H2 A229A6B2?2?86B252=269:5EA2?C692B:92B:
282:2?2 9E3E?82? 2?D2B2 82H2 2CC2 52? A6B46A2D2?
2A2D29C63E2936?5236B86B2;:2D:5225282H2 H2?8366B;2A25236?52D6BC63ED
-E=:C2?=294?D986B252=269:5EA2?C692B:92B:C6BD2 C63ED2?82H2H2?866?82BE9:86B22?36?52D6BC63ED
Gambar 5.1
Ketika kertas ditarik dengan cara dihentakkan, di manakah
koin ini jatuh?
Tokoh
Sir Isaac Newton
lahir di Woolsthorpe, Lincolnshire, Inggris
pada 25 Desember 1642. Pada 1661, Newton berkesempatan
belajar di Trinity College, Cambridge, dan lulus pada 1665.
Penemuannya antara lain dalam bidang matematika jenis baru
saat itu, yakni kalkulus, penemuan dalam bidang cahaya dan warna,
dan hukum-hukum tentang gerak termasuk hukum gravitasi.
Hukum-hukum tentang gerak yang menghebohkan ialah
rumusan dalam jurnalnya yang terkenal, Philosophiae Naturalis
Principia Mathematica atau disebut juga Principia.
Sumber: Jendela IPTEK, 1997
Sir Isaac Newton
1642 – 1727
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Dinamika Gerak
2. Hukum II Newton
2H2H2?8366B;2A252C63E2936?526?H63232?36?52D6BC63ED 36B86B25:A6B46A2D2D2E5:A6B=232D EE6GD?6A6=2;2B:
9E3E?82?2?D2B282H2H2?8366B;2A252C63E2936?5256?82?A6B46A2D2? H2?85:D:3E=2?=6982H2D6BC63ED 6B:ED:?:22?5:=2E2?68:2D2?
C656B92?2 ,6D6=296=2E2?68:2D2?D6BC63ED?525:92B2A2?52A2D 6292:9E3E?82?2?D2B282H22CC236?5252?A6B46A2D2?
36?52H2?8366B;2A25236?52D6BC63ED
,6D6=296=2E2? 131 0 0
?52 D6=29 6292: 9E3E?82?2?D2B22CC2A6B46A2D2?52?A25236?52H2?8B6CE=D2?82H2
H2?85:2=2:?H2D:52C22?= 6B52C2B2?A6B4322?D6BC63ED?52 A6B=699E3E?82?2?D2B282H252?A6B46A2D2??H2H2:DE
N 52AE?92B826C632?5:?82??H2:DE6?E?;E2?EEB2?6=6
322?H2?85::=::36?52H2:DE2CC2 ,642B22D62D:CA6BC222??H2 52A2D5:DE=:CC63282:36B:ED
N 0 + ,
6
5:6?2= C63282: EE 6GD? H2?8
A6B?H2D22??H2C642B2=6?82A252=29329G2A. .. .
.
Aktivitas Fisika 5.2
Hubungan antara Massa, Percepatan, dan Gaya
Tujuan Percobaan Menyelidiki hubungan antara massa, percepatan, dan gaya pada benda yang
mengalami gerak lurus berubah beraturan.
Alat-Alat Percobaan 1.
2 buah balok kayu bermassa m
1
2. Meja
3. Beban bermassa m
2
, m
2
m
1
4. Tali
5. Troli
6. Pewaktu ketik
Langkah-Langkah Percobaan 1.
Susunlah alat percobaan seperti pada Gambar 5.2.
2. Nyalakan pewaktu ketik.
3. Lepaskan troli sehingga troli bergerak.
4. Amati jejak pada pewaktu ketik.
5. Hitunglah percepatan troli tersebut.
6. Lakukan langkah 2 sampai 5 untuk massa di atas troli sebesar 2 m
1
, seperti
pada Gambar 5.2 b.
7. Apakah percepatan yang dialami kedua percobaan itu sama? Mengapa
demikian? 8.
Bagaimana hubungan antara m
1
dan a, juga hubungan antara 2m
1
dan a? 9.
Bagaimana hubungan antara F = m
2
g dan a? m
1
a
b
balok
m
2
m
1
m
1
Gambar 5.2
a Balok bermassa m
1
diletakkan di atas troli dan ditarik oleh gaya F
dari beban m
2
. b Balok bermassa 2 m
1
diletakkan di atas troli dan ditarik oleh
gaya F dari m
2
.
m
2
beban
beban balok
balok
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Mudah dan Aktif Belajar Fisika untuk Kelas X
2H252?A6B46A2D2?252=2936C2B2?F6DBC652?82?2CC236?52 252=2936C2B2?C2=2B =692B6?2:DE82H25:DE=:CC63282:36B:ED
6D6B2?82? 82H2H2?8366B;2A25236?52
2CC236?528 A6B46A2D2?36?52
C
2=2,C2DE2?82H2252=298
C 5:C63ED;E82?6GD? .
,5:567:?:C:2?C63282:.. N
,63E2936?5236B2CC2
836B86B256?82?646A2D2?2G2=
C5:2D2C3:52?852D2B =:4:?6E5:2?36?52D6BC63ED5:36B:82H2D6D2AC62B2956?82?86B236?52 ,6D6=29
6?6AE9;2B2646A2D2?36?526?;25:
C -6?DE2?36C2B82H2D6BC63ED 4
:6D29E: +
C 8
+ C
6BC222?86B2 +
N+
N + +
C N
C
C
3. Hukum III Newton
2D2?C6ED2CD2=:A25232D2?8A9?6B2D6B2D282BD2=:D:52=6A2C C6A6BD:A252 +
682?8D2=:A252;2B23636B2A26D6B:B:?8
2?DE3E9?52C23:=6?2B:D2=:H2?8CE529D6BA2C2?8 ?52D:52 ;2DE93E2?2CEC:?:5:D2?82A=696GD?56?82?6?H2D22?329G2
. .
..,
2526;25:2?D6BC63ED2525E282H2H2?836B=2G2?2?H2:DE82H2D2B: =69 2?2 D6B9252A A9? 5:C63ED . C652?82? A9?
6A6BD292?2?2?256?82?82H2H2?8C225:C63ED. ,62:? 36C2B82H22C:H2?85:6?22?D6B9252AA9?C62:?36C2B82H2B62C:
H2?85:36B:2?A9? N
2H22C:52?82H2B62C:366B;2A2525E236?52H2?836B365256?82? 2B2936B=2G2?2?
6B92D:2? +
EE5:D2B:E:,F6BD:2=632G29 H2?836C2B?H2C636B2D3EE 6;2636B:2?82H25B?86A252
3EEH2?8C2236C2B56?82?82H28B2F:D2C:E:,C69:?882;E=29 65E282H2H2?8366B;2A2523EEC2256?82??= 82BD:52C2=29
A6BC6AC:65E282H2D6BC63ED3E2?A2C2?82?2C:B62C:2B6?2D:52 366B;2A25236?52H2?836B3652
Gambar 5.3
Putut menarik tali yang diikatkan pada pohon.
Contoh
5.1
6?EBEDEE6GD? 8
C
8
C 25:82H2H2?8366B;2A25236?52252=29
4 m
F v
m = 2 kg
Gambar 5.4
Gaya aksi dan gaya reaksi terjadi pada buku dan meja.
N
gaya tekan meja pada buku
gaya tekan meja pada buku
gaya reaksi
w
gaya gravitasi Bumi pada
buku gaya tekan
buku pada meja
gaya aksi
F
F
F F
F
= gaya tarik pohon terhadap
anak
F
,
= gaya tarik anak
terhadap pohon
Sebuah palu bermassa 2 kg diayunkan vertikal ke bawah dengan
kecepatan 20 ms. Palu tersebut menghantam sebuah paku,
mengakibatkan paku masuk sedalam 5 cm ke dalam kayu. Hitunglah gaya
hantam palu.
Tantangan
untuk Anda
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Dinamika Gerak
252 +
3EE6?62?6;2C69:?882636B:2?82H2 2C:H2?82B29?H2632G29 ,63282:B62C:?H26;26?62?3EEH2?8
2B29?H262D2CC69:?882636B:2?82H2B62C: 65E282H2:?: 36C2B?H2C2252?36B=2G2?2?2B29C6BD2 366B;2A2525E236?52H2?8
36B3652 =692B6?2:DEA2C2?82?82H2:?:6BEA22?A2C2?82?2C: B62C:
6C:?DEB3A6C2G2D636B:2?82H22C:6=2=E:82C3E2?86328:2? 36=22?8 ,632=:?H2C63EB2?82C3E2?8B6D6?892C:=2?82H2B62C:
H2?86?H63232?A6C2G2DD6B5B?8656A2?2B6?22CC282C3E2?8 C2?82D64:= 2CD6BC63ED6?H63EB636=22?856?82?646A2D2?D:?88:
2H22C:52B:6C:?DEB36C:?A6C2G2DC2236C2B?H256?82?82H2B62C: 52B:C63EB2?82CD6D2A:2B29?H236B=2G2?2?
4. Gaya Berat
6D:2?526=6A2B2?E2?8=8262D2C2A2H2?8D6B;25: .2?8=82D6BC63ED22?36B86B2?2:9:?8826D:?88:2?2C:E
6E5:2?E2?8=82D6BC63ED22?;2DE9632=:6E: :2?52 6=6A2C2?E2?8=8252B:6D:?88:2?D6BD6?DE52B:D2?29E2?8=82
D6BC63ED;E8222?;2DE96E: .2?8=8222?C6=2=E;2DE96E: 56?82?A6B46A2D2?D6BD6?DE2B6?2252?H282H28B2F:D2C:E:A252E2?8
=82 ,6E236?5222?6?82=2:A6B46A2D2?H2?8C22D2?A25:A6?82BE9:
2CC2?H2 ?52?222?A6B46A2D2?:?:56?82?A6B46A2D2?8B2F:D2C: H2?836C2B?H2
C
52?5:=232?82?56?82? 2B: EE 6GD? H2?8 D6=29 ?52 A6=2;2B: ?52 52A2D
6?E=:C2?82H28B2F:D2C:
8
A25236?5236B2CC2C63282:36B:ED
8
6?82?6?88E?22? 52?6?E=:C2??H2E?DE82H28B2F:D2C: 5:A6B=69
4
Gambar 5.5
Gaya aksi dan gaya reaksi terjadi pada mesin turbo pesawat.
turbin digerakkan oleh gas panas
bahan bakar terbakar di dalam bilik bakar
baling-baling meniup udara ke
sekeliling mesin
aliran udara kompresor tahap kedua
meningkatkan tekanan kompresor tahap
pertama menekan udara masuk
buangan jet
N 6D6B2?82?
482H236B2D?6GD? 2CC236?528
A6B46A2D2?8B2F:D2C:
C
Massa dan berat bukan besaran yang sama. Satuan massa adalah kg dan
satuan berat adalah newton.
Ingatlah
:2A6B46A2D2?8B2F:D2C:5:?D:2?2
C 36B2A236B2D36?52H2?82CC2?H28
5:?D:2?2
4
:6D29E: 8
C
Contoh
5.2
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Mudah dan Aktif Belajar Fisika untuk Kelas X
,6AD?832=2CC2?H2
8D6B=6D25:2D2C=2?D2: 2=D6BC63ED5:D2B:=6982H2 F6BD:2=62D2CC636C2B :2
C
36B2A229A6B46A2D2?H2?85:36B:2? A25232=D6BC63ED
4 :6D29E:
25232=366B;25E282H2H2:DE82H236B2D,52?82H2D2B:F6BD:2=62D2C ,
8
C 6B46A2D2?36?525:D6?DE2?=6982H252?82H2,
.
,
, N
8
C 25:A6B46A2D2?36?52252=29
C
w a
F
Contoh
5.3 Tugas Anda 5.1
Dalam kehidupan sehari-hari, mungkin Anda pernah mendengar
kalimat: “berat badan Indro adalah 60 kg”. Bukankah satuan berat
adalah newton? Apakah timbangan merupakan alat pengukuran berat
atau massa? Bersama kelompok belajar Anda, diskusikan hal
tersebut.
5. Gaya Gesekan
.?DE632?DE?526292:?C6AD6?D2?882H286C62? ?5252A2D6=2E2?131 00
36B:EDE?DE6?822D:
82H286C62?2?D2B232=52?6;2
, 8
C
25:36B2D36?52252=29
Aktivitas Fisika 5.3
2H286C62?D6B;25:A2525E2A6BE22?36?52H2?8C2=:?836BC6?DE9 2?52?D6B52A2D86B2B6=2D:72?D2B265E2?H2 2H286C62?D6BC63ED
6?892C:=2?82H2E?DE6?89232D=2;E36?52 2H286C62?2?D2B2
Gaya Gesekan
Tujuan Percobaan Mengamati gaya gesekan yang terjadi antara dua benda.
Alat-Alat Percobaan 1.
Meja 2.
Balok kayu 3.
Neraca pegas
Langkah-Langkah Percobaan 1.
Susunlah alat percobaan seperti pada gambar. 2.
Ketika balok sedang diam, tarik neraca pegas, kemudian amati gaya yang ditunjukkan neraca pegas.
3. Catat gaya yang ditunjukkan neraca pegas sesaat balok akan bergerak.
4. Tarik neraca pegas sehingga balok bergerak dengan kecepatan konstan.
5. Catat gaya yang ditunjukkan neraca pegas pada saat balok bergerak dengan
kecepatan konstan. 6.
Bandingkan nilai gaya yang ditunjukkan neraca pegas saat balok akan bergerak dan saat balok bergerak dengan kecepatan konstan?
7. Gaya apakah yang ditunjukkan neraca pegas?
balok neraca
pegas
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Dinamika Gerak T
r T
5E236?52H2?836BC6?DE92?32?H25:;EA2:52=269:5EA2?C692B:92B: 2523636B2A22CEC82H286C62?36BC:72D6BE8:2?C652?82?A252
2CECH2?8=2:?82H286C62?36BC:72D6?8E?DE?82? ,6B2?8C:CG26 ?6?52?8C63E293=25:2D2C=2A2?82?36BEAEDD6B;25:82H286C62?2?D2B2
A6BE22?3=256?82?92A2B2?BEAEDC69:?8823=222?36B96?D: A252;2B2H2?8D:52D6B=2=E;2E9 2H286C62?6?89232D=2;E3=2
2524?D9=2:?82H286C62?D:3E=2?D2B232?6?52B22?H2?8 C652?836B86B256?82?;2=2?H2?85:=2=E:?H2C69:?882D:52C=:A 2H2
86C62? E52B2 56?82? C6B2?8 A6?6B;E? A2HE?8 D6B;25: C6A2?;2?8 86B22??H2 3EC2?E52B2H2?86?H6?DE93:52?8A2HE?86BEA22?
82H2A6?89232DD6B9252A=2;EA6?6B;E?C69:?882A6?6B;E?C6=22DC22D D:325:D2?29 252A6B:CD:G2:?:82H286C62?C2?82D36B2?722DD6B9252A
6C6=22D2?A6?6B;E?A2HE?8
6. Gaya Sentripetal F
sp
-6=29?526D29E:329G2646A2D2?252=2936C2B2?F6DBH2?8 6:=::36C2B52?2B29 :22B2952?6=2;E2?36BE329F6DB646A2D2?
22? 36BE329 ;E82 6BE3292? F6DB 646A2D2? 22? 6?:3E=2? A6B46A2D2? 6?EBEDEE6GD?82H26BEA22?A6B2=:2?2?D2B2
2CC236?5256?82?A6B46A2D2?H2?85::=::36?52D6BC63ED :282H2 C6?DB:A6D2=H2?8366B;2A25236?5236B86B26=:?82B36B2DEB2?252=29
A6B46A2D2?C6?DB:A6D2=H2?85::=::36?5236B2CC2252=29 22
82H2C6?DB:A6D2=5:BEEC2?C63282:36B:ED
Gambar 5.6
Gerak turun penerjun payung semakin lambat ketika semakin
dekat dengan tanah.
Sumber:
Physics for You, 2001
+
2 2
2H2C6?DB:A6D2=2B29?H2C6=2=E6?E;E6D:D:AEC2D=:?82B2?52? D682=EBEC56?82?F6DB646A2D2??H2 .?DE6?86D29E:252?H282H2
C6?DB:A6D2=A25286B26=:?82B36B2DEB2?=2E2?68:2D2?36B:ED
Aktivitas Fisika 5.4
Gaya Sentripetal
Tujuan Percobaan Mengetahui arah gaya sentripetal
Alat-Alat Percobaan Tali dan bola pingpong
Langkah-Langkah Percobaan 1.
Ikatkan ujung tali pada bola pingpong. 2.
Putar bola tersebut di atas kepala dengan posisi mendatar. 3.
Apa yang Anda rasakan terhadap gaya tegangan tali? 4.
Putarlah tali lebih cepat lagi. Adakah pengaruh kelajuan bola dengan gaya tegangan tali?
5. Apa kesimpulan Anda dari percobaan ini?
6B92D:2? +
:2 82H2 36B2D 3=2 5:232:2? 8232B D6BC63ED6A6B=:92D2?82H282H2H2?8366B;2A2523=2H2?85::2D
56?82?D2=:52?5:AED2B56?82?D2?82?C63282:D:D:AEC2D?H2 2A2D 5:2D22?329G23=2D6BC63ED36B86B26=:?82B 2H2D682?82?D2=:
6BEA22? 82H2 H2?8 6?H63232? 36?52 D6BC63ED 36B86B2 6=:?82B
Gambar 5.7
Gaya sentripetal menuju pusat lingkaran.
N
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,63E293=236C:36B2CC285::2D56?82?C6ED2CD2=:H2?8A2?;2?8?H24 6E5:2?5:AED2B636?DE=:?D2C2?6=:?82B56?82?6=2;E2?
C -6?DE2?
82H2C6?DB:A6D2=3=236C:D6BC63ED 4
:6D29E: 88
4 +
C
R = 80 c m
m = 50 g
Contoh
5.4
C
0 + ,
652A2D5:DE=:CC63282:36B:ED +
6B=E ?52 A6B92D:2? 329G2 82H2 C6?DB:A6D2= 6BEA22? CE2DE :CD:=29E?DEB6CE=D2?82H2H2?82B29?H26?E;EAEC2D
2H2C6?DB:A6D2=;E8252A2D?52D6E:A25286B26=:?82B36?52 36?52=2?8:DD6B9252A36?52=2?8:D=2:??H2 ,63282:4?D93E=2?H2?8
C6=2=E6?86=:=:?8:E: 6?82A2 E=2? C6=2=E 6?86=:=:?8: E: 2H2 2A229 H2?8
36BD:?52C63282:82H2C6?DB:A6D2=2B:EE6GD?5:6D29E:329G2 2?D2B25E23E2936?52H2?86:=::2CC252?5:A:C292?=69;2B2
D6BD6?DE 366B;2 C63E29 82H2 D2B:6?2B: H2?8 36C2B?H2 C632?5:?8 56?82? 2CC2 36?5236?52 D6BC63ED 52? 36B32?5:?8 D6B32=: 56?82?
E25B2D;2B2A:C292?D2B236?5236?52D6BC63ED 2H2:?:5:C63EDC63282: 82H28B2F:D2C: 2H2:?:=29H2?86?H63232?E=2?36B86B26?86=:=:?8:
E: 25: H2?8 36BA6B2? C63282: 82H2 C6?DB:A6D2= A252 86B2 E=2? 6?86=:=:?8:E:252=2982H28B2F:D2C:2?D2B2E=2?52?E:
N
?52D6=296?86D29E:329G286B23E=2?5:A6?82BE9:82H2D2B:E: :DE?8=29 36C2B82H2D2B:E:D6B9252A3E=2?D6BC63ED .?DE6?86B;22?DE82C:?:?52
A6B=E6?86D29E:36C2B2?36C2B2?E:52?3E=2?H2?85:3EDE92?52=2 A6B9:DE?82?D6BC63ED
Mari Mencari Tahu
2H2C6?DB:A6D2=5:A6B=6956?82?6?88E?2 2?A6BC222?
CA
+
2
CA 2
4 ms 0,1kg
2 N 0,8 m
25:82H2C6?DB:A6D2=3=236C:252=29
Sebuah benda bermassa 200 gram diikat dengan tali ringan. Kemudian,
diputar secara horizontal dengan kecepatan sudut tetap 5 rads.
Panjang tali tersebut adalah 60 cm. Berapakah besar gaya sentripetal
pada benda tersebut? a.
0,3 N b. 0,6 N
c. 3 N
d. 6 N e. 30 N
UAN , 2001
Pembahasan Diketahui:
m = 200 gram = 0,2 kg = 5 rads
= 60 cm = 0,6 m F
sp
=
2
v m
R
Dalam kasus ini, = R.
Dengan demikian, F
sp
=
2
v m
R
F
sp
=
2
m R
F
sp
= 0,2 kg 5 rads
2
0,6 m F
sp
= 3 N Jadi, gaya sentripetal yang bekerja
pada benda adalah 3 N.
Jawaban: C
Pembahasan
Soal
Kata Kunci
• Hukum I Newton
• Hukum II Newton
• Hukum III Newton
• gaya aksi
• gaya reaksi
• gaya gesekan
• gaya sentripetal
2H2:?:;E8252A2D5:B2C22?=69D2?82??52 2H2D682?82? D2=::?:6BEA22?82H2H2?82B29?H26?E;EAEC2D52?A6?H6323
3=2D6BC63ED36B86B26=:?82B 2=292=:?:H2?836BA6B2?C63282: 82H2C6?DB:A6D2=
252=2982H2D682?82?D2=:
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Dinamika Gerak
B. Penerapan Hukum Newton
252328:2?:?:?5222?6A6=2;2B:3636B2A2A6?6B2A2?9EE 6GD?52=269:5EA2?C692B:92B:
1. Gerak Benda pada Bidang Datar
,63E2936?52D6B=6D2A2523:52?852D2B=:4:?C6A6BD:A252 + 6E5:2? 5:36B: 82H2 6?52D2B 9:?882 36?52 36B86B2 =EBEC
56?82?A6B46A2D2? 2H282H2H2?8366B;2A252CE3E.252=29
.
, 6?52D:5236B86B2D6B9252ACE3E.22
.
, N
, 2H2H2?8366B;2A252CE3E-
-
Tes Kompetensi Subbab
A
, +22 1 , :DE?882H2H2?85:3EDE92?C63E293:=H2?82CC2
?H2
8E?DE6?42A2:646A2D2?
C52=2 G2DEC
,63E2982H2366B;2A25236?5236B2CC2 52?
A6B46A2D2?H2?85:D:3E=2?
C 2H2H2?8C22
366B;2A25236?52=2:?36B2CC2 A6B46A2D2?H2?8
5:D:3E=2?
C 2 6B2A229?:=2:B2C:
1 2
3 :2 52?
5:823E?836B2A2A6B46A2D2?H2?8 5:92C:=2?=6982H2
,63E293EC2CC2?H2 836B86B256?82?6 46A2D2?
;2 3:=5:B652?36B96?D:C6D6=29
6?6AE9;2B2
-6?DE2?82H2B6H2?8 366B;2A2523:=D6BC63ED
?52C652?836B2525:52=2C63E29A6C2G2DD6B32?8 A2526D:?88:2?
2: 6B2A2A6B
C6?29A6BE3292?36B2D3252??52 ,6AD?832DE32D2H2?82CC2?H2
8D6B=6D25:2
5:2D2CD2?29 6E5:2?32DED6BC63ED5:D2B:62D2C 56?82?82H2C6=22
C=2=E5:=6A2C2? :2
C D6?DE2? D:?88: 2C:E H2?8
5:42A2:?H2 ,63E293=236B2CC2
8B25::2DA252E;E?8
C6ED2CD2=:H2?8A2?;2?8?H24 =236BAED2B52 =2=:?82B2?9B:I?D2=56?82?6=2;E2?D6D2A
C
:DE?8D682?82?D2=: ,63E29A:B:?82?56?82?;2B:;2B:45:AED2B56?82?
646A2D2?CE5ED
B25
C -6?DE2?A6B46A2D2?52? 82H2C6?DB:A6D2=C63E29D:D:36B2CC2
8H2?836B252
5:A:?88:BA:B:?82?D6BC63ED ,63E29 3=2 36B2CC2
8 5:AED2B 6?8:D2B:
=:?82B2?F6BD:2=H2?8B25:EC?H256?82?=2;E C :DE?8D682?82?2C:E52?D682?82?:?:
E D2=: H2?8 6?89E3E?82? 3=2 6 AEC2D =:?82B2?;:2
C
,63E296?52B22?6?:E?85:=:?D2C2?;2=2?6? 52D2B2C2B56?82?;2B:;2B:6=6?8E?82?2CC2
6?52B22? 52? A6?EA2?8 8 -6?DE2? 646A2D2?2C:E282B6?52B2?D:52C=:A;:282H2
86C62?2?D2B232?52?;2=2? ,63E293:=6=6G2D:;2=2?463E?8 :6D29E:
B25:EC
2CC23:=36C6BD2A6?EA2?8?H2 8 2H2D62?3:=D6B9252A;2=2? :2
A6B46A2D2?8B2F:D2C:
C D6?DE2?=2;E3:=A252
C22D65E5E2?D6BD:?88:
Gambar 5.8
Gaya-gaya yang bekerja pada balok.
N F
w
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N 6D6B2?82?
A6B46A2D2?
C 82H2
2CC28
2523:52?852D2B=:4:?D:5225282H286C62?H2?8366B;22?D2B236?5256?82? 3:52?8 ,63E2936?5236B2CC28D6B=6D2A2526;26?52D2B=:4:? 6?52:DE
5:36B:82H26?52D2BC636C2B 6B2A2A6B46A2D2?36?52:DE 4
:6D29E: 8
8
C 25:A6B46A2D2?36?52
C
N
w F
= 10 N
,63E293:=36B2CC2
836B86B256?82?646A2D2?
;2 6B2A229 82H2H2?85:A6B=E2?E?DE6?86B6282B3:=36B96?D:A252;2B2
4 :6D29E:
8 +
;2
C 3:=36B96?D:36B2BD:+
+ N+
N
C N
C N
C
6?82? 6?88E?22?EE6GD?5:A6B=69
8N
C N
N7 25:282B3:=36B96?D:A252;2B2
92BEC5:6B;22?82H2C636C2BO
H2?82B29?H236B=2G2?2?56?82?2B2986B236?52
2. Gerak pada Bidang Miring
,63E2936?526:=::82H236B2D , D6B=6D2 A252 3:52?8 :B:?8=:4:?636?DECE5ED6:B:?82? D6B9252A82B:C9B:I?D2=
2H2H2?8366B;2A25236?52252=2982H2?B2= B2982H2?B2= D682=EBECD6B9252A3:52?8C6?DE9C6A6BD:A252 +
,E3E-C6;2;2B3:52?8:B:?852?CE3E.D682=EBEC3:52?8:B:?8 A?6?82H236B2DA252
CE3E-,
-
C:? CE3E.,
.
4C
Gambar 5.9
Gaya-gaya yang bekerja pada benda yang diletakkan pada
bidang miring mg
N
mg cos mg sin
licin
Sebuah balok bermassa 2 kg terletak di atas bidang datar licin. Pada balok
tersebut dikenakan gaya tarik dengan arah 60° terhadap arah
mendatar. Hitunglah percepatan balok tersebut.
Tantangan
untuk Anda Contoh
5.5
Contoh
5.6
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Dinamika Gerak
N
v
mg cos
mg sin
mg
,6AD?832=H2?82CC2?H2
85:=E?4EB2?,EC2?DA2523:52?8:B:?8=:4:?D2?A2 646A2D2?2G2= ,E5ED6:B:?82?3:52?8D6B9252A9B:I?D2=J :2
C
36B2A229 2 82H2?B2=A25232=
3 646A2D2?32=C6D6=296=E?4EBC6=22C 4
:6D29E: 8
J C
2 A?6?82H236B2DA252CE3E. ,
.
,4C 4CJ
8
C 6?52D:5236B86B262B29CE3E.C69:?882
-
,
H
25:82H2?B2=?H2252=2910 3 3 A?6?82H236B2DA252CE3E-
,
-
,C:? C:?J
8
C 6?5236B86B2C6A2?;2?8CE3E-3:52?8:B:?8C69:?882
-
,
-
4C N
+6CE=D2?82H282H2A252CE3E-252=29
-
C:? C:?
6D6B2?82? 82H2?B2=
2CC236?528 CE5ED6:B:?82?
A6B46A2D2?8B2F:D2C:
C N
2H282H2H2?8366B;2A252CE3E.252=29
.
N,
.
4C 6?52D:5236B86B2D6B9252ACE3E.22
y
F
Contoh
5.7
Perhatikan perubahan pada Contoh 5.7.
Jika sudut diubah
menjadi 60°, berapakah gaya normal pada balok tersebut dan berapakah
kecepatan balok setelah meluncur selama 3 sekon? Buatlah kesimpulan
tentang perubahan sudut
terhadap gaya normal dan kecepatan benda.
Tantangan
untuk Anda
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Mudah dan Aktif Belajar Fisika untuk Kelas X
3. Gerak Benda-Benda yang Dihubungkan dengan Tali
6B92D:2? +
E232=D6B=6D25:2D2C3:52?852D2B =:4:? 65E232=D6BC63ED5:9E3E?82?56?82?C6ED2CD2=:H2?82CC2?H2
5:232:2? ,22D82H25:6B;22?22D2=:6:=::D682?82?C636C2B H2?8366B;2A25232=
+6CE=D2?82H2A25232=A252CE3E-252=29
-
N +6CE=D2?82H2A25232=A252CE3E-252=29
-
N 0 + ,
6
5:CE3CD:DEC:2? 6 52=2 0 + ,
6
C69:?8825:A6B=69
N 6D6B2?82?
A6B46A2D2?36?52
C 82H2D2B:
2CC236?528 2CC236?528
C 2=36B86B2D2?A2646A2D2?2G2=H2:DE+
646A2D2?A252C252=29 +
+ C
C
C 646A2D2?32=C6D6=29C252=29
C
E236?5252?2C:?82C:?82CC2?H2852?85:2D2C3:52?852D2B=:4:? 52?5:9E3E?82?56?82?D2=:C6A6BD:A2528232B :232=5:D2B:=6982H2
D6?DE2? 2 A6B46A2D2?36?52
3 D682?82?D2=: 4
:6D29E: 8
8
A B
T F
T
Gambar 5.10
Gaya F menarik balok A dan balok B.
B A
T T
F
licin
Perhatikan gambar berikut.
Berapakah massa tabung B?
Tantangan
untuk Anda Contoh
5.8
C D
12 kg 15 kg
20 kg
tegangan tali
A B
tegangan tali
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Dinamika Gerak
4. Gerak Benda yang Dihubungkan dengan Tali Melalui Katrol
E236?5236B2CC2 52?
5:9E3E?82?=69C6ED2CD2=:6=2=E: C63E292DB=C6A6BD:A252 +
2H286C62?2DB=5:232:2?
?882A 22
22? 36B86B2 6 32G29 C62B29 56?82? A6B46A2D2?8B2F:D2C:C652?82?
36B86B262D2C36B=2G2?2?2B29 56?82? A6B46A2D2? 8B2F:D2C: C69:?882 36B?:=2: ?682D:7 65E2 36?52
6:=::A6B46A2D2?52?D682?82?D2=:H2?8C22 -:?;2E2?A25236?5236B2CC2
N N
N -:?;2E2?A25236?5236B2CC2
N N
=692B6?2D:5225282H286C62?A2522DB=C6E2D682?82?D2=: C2236C2B 2B:0 + ,
6
52?0 + ,
6 5:A6B=69
N
N
6B92D:2? +
6?5236B2CC2 D6B=6D25:2D2C3:52?8
52D2BC652?82?36?5236B2CC2 D6B82?DE?83632CA252C6ED2CD2=:
2H286C62?A2522DB=52?2CC2D2=:5:232:2? D:?;2E2?A25236?5236B2CC2
2
88
C 25:A6B46A2D2?36?52
C
3 8
C
25:D682?82?D2=:
N
Gambar 5.11
Dua buah benda dihubungkan dengan tali melalui sebuah katrol.
Gambar 5.12
Dua benda dihubungkan dengan tali melalui katrol dan m
1
terletak pada bidang datar.
m
2
m
1
N T
T T
T
w
1
= m
1
g
w
2
= m
2
g
licin
T T
a T
T
a
m
1
g
m
2
g
licin
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Mudah dan Aktif Belajar Fisika untuk Kelas X
-:?;2E2?A25236?5236B2CC2
2B:0 + ,
6 52?0 + ,
6 5:A6B=69 N
E236?5252?2C:?82C:?82CC2?H2852?
85:9E3E?82?56?82?D2=: 6=2=E:C63E292DB==:4:? 6B2A2A6B46A2D2?52?D682?82?D2=:;:265E236?52
5:=6A2C2?
C
4
6D:265E236?525:=6A2C2?36B86B2632G2952?36B86B262D2C2B6?2 65E236?526:=::A6B46A2D2?C22
2 8
8N
8 8
8
C C
25:A6B46A2D2?65E236?52
C 3
8
C N8
C
8
C 25:D682?82?D2=:65E236?52
2B:CECE?2?36?5236?52A2528232BD6?DE2?A6B46A2D2?36?5252?D682?82? C6D:2AD2=:;:2
8 852?
852?3:52?8=:4:?
C
4
:236?525:=6A2C2?36?5236B86B2 632G29 52?36B86B262?2?56?82?
A6B46A2D2?H2?8C22 2
N
Perhatikan gambar berikut.
Hitunglah percepatan benda A dan tegangan tali.
20 kg katrol licin
5 kg 30°
licin
A B
C T
1
T
2
T
3
A B
A B
T T
w
A
w
B
Tantangan
untuk Anda Contoh
5.10
Contoh
5.9
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Dinamika Gerak
252B2?82:2?C6A6BD:8232B36B:ED2CC236?5252?2C:?82C:?8852? 8 2CC22DB=52?D2=:5:232:2?
C
-6?DE2?A6B46A2D2?36?5252? D682?82?D2=:
4 :6D29E:
8
8
C 8 8 8
C C
25:A6B46A2D2?C6E236?52C22H2:DE
C 3 -:?;2E2?A25236?52
8
C 25:D682?82?D2=:
4 -:?;2E2?A25236?52
8
C N
8
C 25:D682?82?D2=:
Gambar 5.13
Dua benda dihubungkan dengan tali melalui dua katrol.
5. Gerak Benda Dihubungkan Tali Melalui Dua Katrol yang Salah Satunya Dapat Bergerak
252 B2?82:2? 36?52 52? 36?52 C6A6BD: + A6B46A2D2? 36?52 A252 2DB= 36B86B2 3632C 252=29 C6D6?829 52B:
N
N
Contoh
5.11
m
B
g
B A
m
A
g N
T T
T
licin
A6B46A2D2? 36?52 A252 2DB= D6D2A C69:?882 6BC222?
A6BC222?H2?836B=2EA252B2?82:2?D6BC63ED252=29C63282:36B:ED -:?;2E2?A25236?52
-:?;2E2?A25236?52 ,
N N
N
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Mudah dan Aktif Belajar Fisika untuk Kelas X
8 C
-:?;2E2?A25236?52 8
-:?;2E2?A25236?52 N
8
C N
8
C N
0 + ,52?0 + ,5:CE3CD:DEC:2?C69:?8825:A6B=69 8
8
C N
8 8
C
N8 8
8
C C
2B:0 + ,5:A6B=69 8
C
25:A6B46A2D2?36?52252=29
C 52?D682?82?D2=:252=29
6. Gaya Tekan pada Alas Lift
6B92D:2? +
,63E2932=36B2CC2D6B=6D25:52=2 =:7DH2?8C652?836B86B2 6?EBEDEE6GD?82H2D62?32=
A2522=2C=:7D,C2256?82?82H2?B2=36?52 2 1 , +
=:7D36B86B2F6BD:2=62D2C56?82?
646A2D2?D6D2A22B6CE=D2?82H2H2?8366B;2A25236?52252=29?=
, 22,,
3 1 , +
=:7D36B86B2F6BD:2=62D2C56?82? A6B46A2D2?D6D2A22B6CE=D2?82H2H2?8366B;2A25236?52252=29
22,, 4 1 , +
=:7D36B86B2F6BD:2=62D2C56?82?
A6B=232D2?N22B6CE=D2?82H2H2?8366B;2A25236?52252=29 N
N
A
B T
T T
m
A
= 3 kg
m
B
= 4 kg m
A
g
m
B
g
Gambar 5.14
Sebuah balok bermassa m terletak di dalam lift yang sedang bergerak.
a c
d
mg = w N
mg = w N
a v
mg = w a
N
w
v w
w v
b
mg = w N
a
w
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Dinamika Gerak
H2?82CC2?H2836B5:B:5:52=2C63E29=:7DH2?8C652?836B86B262D2C 56?82?A6B46A2D2?
C
:2A6B46A2D2?8B2F:D2C:E:
C 36B2A229
82H2D62?2:A252=2?D2:=:7D 4
6?82?6?88E?22?0 + ,
6
5:A6B=69 8
C
C 25:82H2D62?A252=2?D2:=:7D252=29
Tes Kompetensi Subbab
B
, +22 1 , ,63E29D236B2CC28D6B=6D25:A6BE22?
=2?D2:=:4:? :2D2D6BC63ED5:D2B:56?82?82H2 C636C2B36B2A229646A2D2?D2D6BC63ED
,63E2936?525:=E?4EB2?=69A2523:52?8 :B:?8=:4:? :22CC236?52D6BC63ED852?CE5ED
6:B:?82?3:52?8D6B9252A9B:I?D2=J9:DE?8=29 646A2D2?36?52C6D6=2936B86B2
C
6B92D:2?8232B36B:ED
m
1
m
2
:2A6B32?5:?82?2?D2B2 52?
252=29 9:DE?8=29A6B46A2D2?86B2A2522DB=D6BC63ED
C E23E2936?525:CECE?C656::2?BEA2C69:?882
D2A2C6A6BD:A2528232B36B:ED :22CC2852?2CC2
89:DE?8=29
D682?82?D2=:52?A6B46A2D2?36?526D:236?52 6=E?4EB
,:DBECC652?836B5:B:5:52=2=:7DH2?8C652?836B 86B2632G2956?82?A6B46A2D2?
C 6B2A229
82H2D62?2:,:DBECA252=2?D2:=:7D
N N
A
B
Contoh
5.12
22,
, 5 1 , +
=:7D36B86B2F6BD:2=632G2956?82?
A6B46A2D2?D6D2AB6CE=D2?82H2H2?8366B;2A25236?52252=29
22,
,
Kata Kunci
• bidang datar
• bidang miring
• gaya normal
• gaya berat
• tegangan tali
• katrol
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100
Mudah dan Aktif Belajar Fisika untuk Kelas X
66?82BE9: 6A6=2;2B:
, +
H2?8366B;2A252CE2DE36?5236C2B?H236B 32?5:?8=EBEC56?82?82H252?36B32?5:?8D6B
32=:56?82?2CC236?52 :BEEC2?56?82?
EE6GD?6?H2D22?329G2;:2 36?52A6BD226?86B;22?82H2A25236?52
65E236?5265E222?6?86B;22?82H2 A252 36?52 A6BD22 H2?8 36C2B?H2 C22
D6D2A: 2B29?H2 36B=2G2?2? :BEEC2? 56?82?
2C: B62C:
2H266?82BE9:86B236?52 ,2DE2?82H252=2,252=29?6GD?
,2DE ?6GD? 5:567:?:C:2? C63282: 82H2 H2?8636B:2?A6B46A2D2?
C
A252 CE2DE36?52H2?82CC2?H28
EE6GD?6?H2D22?329G2;:2 B6CE=D2?82H282H2H2?8366B;2A25236?52
C2256?82??=36?52D6BC63ED22?D6D2A 5:2 2D2E 36B86B2 =EBEC 36B2DEB2?
:BEEC2?56?82? EE 6GD? 6?H2D22? 329G2
A6B46A2D2? H2?8 5:D:3E=2? =69 82H2
D:3E=2B6?2
EE 6GD?
6?H2D22?
EE 6GD?
EE 6GD?
6?H2D22? 6?H2D22?
:2 36?5222?
K 5:2+2D2E K 36B86B2=EBEC36B2DEB2?
Peta Konsep Rangkuman
2H2
9E3E?82??H2
6B2
Setelah mempelajari bab ini, tentu Anda mem- peroleh manfaat, di antaranya Anda mengetahui bagai-
mana hubungan antara massa m, gaya F, dan percepatan a. Dapatkah Anda menyebutkan manfaat
Refleksi
lain Anda mempelajari bab ini? Dalam mempelajari bab ini, apakah ada materi yang Anda anggap sulit
untuk dipahami? Jika ada, diskusikan dengan teman atau tanyakan kepada guru.
2C:
N
B62C:
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101
Dinamika Gerak
0 0 12 4 ,5 ,. ,1. 1 , , . 22 1 , :236?5292?H25:A6?82BE9:=69C63E2982H236?52
22?36B86B256?82? 2 646A2D2??CD2?C62B2956?82?2B2982H2
3 646A2D2??CD2?36B=2G2?2?2B2956?82?2B29 82H2
4 A6B46A2D2??CD2?36B=2G2?2?2B2956?82?2B29 82H2
5 A6B46A2D2??CD2?C62B2956?82?2B2982H2 6 36?52D6D2A5:2
,63E2982H26?H63232?A6B46A2D2?
C A252
36?52H2?836B2CC28 :282H2:DE366B;2A252 36?52H2?836B2CC2882H2:DE22?636B:2?
A6B46A2D2?C636C2B 2
C
5
C 3
C
6
C 4
C
.?DE6A6B46A2D36?52H2?82CC2?H2852B: 646A2D2?
C6?;25:
CC6=22C5:A6B=E2?
82H2C636C2B 2
5 3
6 4
,63E2936?5236B2CC2
86=E?4EBA2523:52?8 :B:?856?82?646A2D2?D6D2A :2CE5ED6:B:?82?
JB6CE=D2?82H2H2?8366B;2A25236?52252=29 2
5 3
6 4
+6CE=D2?82H2A252C63E293:=H2?836B86B2=EBEC 36B2DEB2?5:;2=2?H2?86?52:252=29
2 C2256?82?82H2?B2= 3 C2256?82?82H236B2D3:=
4 C2256?82?2CC236?52 5 C2256?82?36B2D3:=5:EB2?8:82H2?B2=
6 ?= -:8232=52?5:=6D22?C656:2:?BEA2
36B:A:D5:2D2C3:52?852D2BC6A6BD:A2528232B B27:36B:ED6?E?;E2?9E3E?82?A6BA:?5292?
D6B9252AG2DE52B:5E236?52H2?82CC2?H2C22 H2?8 5:6B;22? =69 82H2
52? C69:?882
6?892C:=2?A6B46A2D2? 52?
2=5:C6?DE956?82?82H26?52D2BC69:?882 82H2D6BC63ED5:D6BEC2?=69636?5252?
C6=2?;ED?H2636?52 2H282H2D6BC63EDH2?8 6BEA22?A2C2?82?2C:B62C:252=29
2 52? 5
52? 3
52? 6 52?
4 52?
A B
C F
1
F
2
F
3
F
4
2B:8B27:52A2D5:C:AE=2?329G2 2
52? 3
52? 4
52? 5
52? 6
52? B27:A6B46A2D2?C63282:7E?8C:B6CE=D2?82H2A252
CE2DE36?52C6A6BD:A2528232B36B:ED
s 1
2
t
2CC236?52D6BC63ED252=29 2 8
5 8 3 8
6 8 4 8
6B52C2B2?EE6GD?52A2D5:C:AE=2? 329G2;:282H2H2?8366B;2A252C63E2936?52
36BD23292CC236?52D6BC63ED 2 36BEB2?852?A6B46A2D2?36BD2329
3 36BD232952?A6B46A2D2?36BEB2?8 4 D6D2A52?A6B46A2D2?36BEB2?8
5 D6D2A52?A6B46A2D2?36BD2329 6 36BD232952?646A2D2?36BEB2?8
,63E29D236B2525:2D2C3:= H2?8C652?836B86B2A6B92D:
2?8232B ,642B2D:32D:323:=
5:B6C69:?882 2 D222?D6D2A
5:2 3 D222?36B86B2
6C2A:?8 4 D222?36B86B26C2A:?82?2?
5 D236B86B26C2A:?8:B: 6 D236B86B2656A2?
2 6
5 10
ams
2
FN
F
Tes Kompetensi Bab 5
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102
Mudah dan Aktif Belajar Fisika untuk Kelas X
,63E2936?52D6B=6D2A2523:52?8:B:?8 2H2?B 2=A25236?52:DE252=29
2 C2256?82?36B2D36?52 3 =63:936C2B52B:A25236B2D36?52
4 =63:964:=52B:A25236B2D36?52 5 C2256?82?2CC236?52
6 C222D2E=63:964:=52B:A25236B2D36?52 6?52H2?82CC2?H25:D6A2D2?5:2D2C3:52?8
:B:?8H2?8=:4:?56?82?CE5ED6:B:?82? D6B9252A 3:52?8 9B:I?D2= :2 A6B46A2D2? 8B2F:D2C:
A6B46A2D2?H2?8D6B;25:A25236?52D6BC63ED252=29 2 C:?
5 C:?
3 C:? 6 4C
4 C:? ,63E2936?5236B2CC236B252A2523:52?8:B:?8
H2?8=:4:?56?82?CE5ED6:B:?82?JD6B9252A9B: I?D2= :2A6B46A2D2?8B2F:D2C:A6B46A2D2?36?52
252=29 2
5
8
3
8
6
8
4
8
6B92D:2?CECE?2?36?5236?5236B:ED ,63E293=236C:5:82?DE?82?A252=2?8:D=2?8:DC6A6BD:
A2528232B36B:ED
6C2B?H2A6B46A2D2?52?D682?82?D2=:36BDEBED DEBED
2
C 52? 5
C
52? 3
C
52? 6
C
52? 4
C
52? ,E2DE36?5236B2CC28D6B=6D2A2523:52?8:B:?8
56?82?6:B:?82?JD6B9252A9B:I?D2= 2H2?B 2=H2?8366B;2A25236?52252=29
2 5
3 6
4 ,63E2936?5236B2CC28D6B=6D2A2523:52?852D2B
5:D2B:56?82?82H2
F6BD:2=62D2C 2H2?B2= H2?8366B;2A25236?52:DE252=29
2 5
3 6
4
9 kg
1 kg
6?H2D22?D682?82?D2=:52?,6?H2D22?36B2D 3632? 2?86BEA22?A2C2?82?82H22C:B62C:
252=29 2
52?, 5
52? 3
52?, 6
52? 4
52? 6B52C2B2?CECE?2?36?5236?52A2528232B6;2
52?2DB=5:2?882A=:4:?C6AEB?2
:236?525:=6A2C2?D682?82?D2=:36C2B?H2 2
5 3
6 4
?:D236B2CC285:D:32?85:52=2=:7DH2?8 C652?86=E?4EB632G2956?82?A6B46A2D2?D6D2A
C :2
C
36B2D?:D25:52=2=:7D 252=29
2 5
3 6
4 2H2?B2=A2522:,:DBECH2?836B2525:52=2
=:7D=63:936C2B52B:A25236B2D?H2 2=:?:D6B;25:;:2=:7D 52=262522?
2 5:2 3 36B86B2632G2956?82?646A2D2?D6D2A
4 36B86B262D2C56?82?A6B46A2D2?D6D2A 5 36B86B2632G2956?82?A6B46A2D2?D6D2A
6 36B86B262D2C56?82?A6B=232D2?
A B
C T
T
2 kg 3 kg
3 kg
T
2
T
1
T
3
w
w
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103
Dinamika Gerak
4 .1 ,5 ,21, ,1. 1 ,63E2932=36B2CC285:D2B:=6982H26?52D2B
5:2D2C3:52?852D2B=:4:? 6B2A229A6B46A2D2? 32=D6BC63ED
,63E2936?5236B2CC2836B86B256?82?6 46A2D2?
C 6B2A22936C2B82H2A6B=2G2?2?H2?8
5:A6B=E2?282B36?52D6BC63EDD6A2D36B96?D:52B: D6A2DC6E=2
,63E2932=36B2CC286=E?4EBD2?A2646A2D2? 2G2=5:2D2C3:52?8:B:?8H2?8=:4:?C6AEB?2 :2
D2? 6BEA22?CE5ED6:B:?82?3:52?8
52?
C D6?DE2?
2 82H2?B2=A25236?52 3 A6B46A2D2?H2?8D:3E=A25236?52
4 ;2B2H2?85:D6AE9C6D6=29C E236?5252?5::2D2?A252E;E?8E;E?8D2=:
H2?85:C2?8ED2?A2522DB=C6A6BD:A2528232B 6B92D:2?CECE?2?8232B36B:ED
2CC265E236?522C:?82C:?8 852?
8
C ,E5ED6:B:?82?3:52?8
D6B9252A9B:I?D2=J :23:52?8=:4:?C6AEB?2 D6?DE2?
2 82H2?B2=A25236?52 3 2B2986B265E236?52
4 A6B46A2D2?86B265E236?52 5 D682?82?D2=:
6B92D:2?CECE?2?8232B36B:ED
A B
2CC252?2C:?82C:?8852?8 6;2 =:4:?C6AEB?22CC2D2=:52?2DB=5:232:2? :2
C D6?DE2?
2 A6B46A2D2?36?5252? 3 D682?82?D2=:?H2
2CC252?2C:?82C:?8852?8 ,E5ED3:52?8:B:?8D6B9252A9B:I?D2=J52?
C -6?DE2?
2 2B2986B236?52 3 A6B46A2D2?36?52
4 D682?82?D2=: E23E293=252?H2?82C:?82C:?82CC2?H2
85::2D56?82?D2=:52?5:82?DE?8A252=2?8:D =2?8:D=:7D :2=:7D36B86B262D2C56?82?A6B46A2D2?
C 36B2A2D682?82?C6D:2AD2=:
C
E236?5252?5::2D2?A252E;E?8E;E?8D2=: H2?85:C2?8ED2?A2522DB=C6A6BD:A2528232B
36B:ED
A B
30°
:52=2C63E29=:7D5:D6A2D2?D:32?82?3252? ,22D =:7D52=262522?5:26B:6?:32?83252??H2
C69:?8825:52A2D2?36B2D6B: :2
C D6?DE2?A6?E?;E2?D:32?82?;:2
2 =:7D36B86B2F6BD:2=62D2C56?82?A6B46A2D2? D6D2A
C
3 =:7D36B86B2F6BD:2=62D2C56?82?A6B=232D2? D6D2A
C
4 =:7D36B86B2F6BD:2=632G2956?82?A6B46A2D2? D6D2A
C
5 =:7D36B86B2F6BD:2=632G2956?82?A6B =232D2?D6D2A
C
,6C6B2?8H2?82CC2?H285:D:32?85:52=2=:7D H2?8C652?836B86B262D2C56?82?A6B46A2D2?D6D2A
C :2A6B46A2D2?8B2F:D2C:252=29
C
D6?DE2? 36B2DB2?8:DE5:52=2=:7D
2CC236?5252?2C:?8 2C:?8852?
8 2DB=
5:2?882A=:4:?C6AEB?2 :2 A6B46A2D2?8B2F:D2C:
C
D6?DE2? 2 2B2986B236?52
3 A6B46A2D2?86B236?52 4 D682?82?D2=:
A
A N
T
B m
A
g
m
B
g T
T B
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104
Mudah dan Aktif Belajar Fisika untuk Kelas X
Proyek
Semester 1
252C66CD6B:?:?52D6=296A6=2;2B:D6?D2?8?C6A52?AB:?C:A52C2B :?62D:252?5:?2:236?52D:D: .?DE6?:?82D2?A62922?6?86?2:
?C6AD6BC63ED?525:DE82C2?E?DE6=2E2?68:2D2?C66CD6BC642B2 36B6=ANB2?8 2?82968:2D2?H2?892BEC?52=2E2?5:EB2:2?
A252ABH6C66CD6B:?: ,63282:DE82C29:B68:2D2?6=A?5292BEC63E2D =2AB2?68:2D2?C66CD6BH2?822?5:AB6C6?D2C:2?5:29:BC66CD6B5:9252A2?
6=A=2:?52?8EBE :C:2?52 ,:CD62D:2A6?E=:C2?=2AB2??H2D6B5:B:2D2C E5E=-E;E2?=2D52?292?BC65EB6B4322?2D2?2=:C:C2D2C6BD2
6C:AE=2?52?,2B2?D6B9252AA6?6=:D:2?H2?8D6=295:=2E2?
Gerak Lurus Beraturan dan Gerak Lurus Berubah Beraturan
22 , 1 , 6A6=2;2B:C63E2936?52H2?836B86B2=EBEC36B2DEB2?52?36B86B2=EBEC36BE329
36B2DEB2? 1 , ,
2A2?=:?D2C2?
6=6B6?85:26D6B
L
4 6?882B:C2?;2?8
,
3E29 -EAE2?
2AEBDE=:C2D2ECA:5= -02- ,
,ECE?=292=2D2=2DC6A6BD:A2528232B36B:ED
-2?52:52?9:DE?8;2B22?D2B2D:D:2G2=D:D:52?D:D: 6A2C2?6=6B6?852B:D:D:9:?8826?86=:?5:?86D:D:6=2=E:D:D:
:DE?8G2DED6AE96=6B6?852B:6D:D:52?52B:D:D:6D:D: 1 1 ,2B2N36B:C2B2?D2B2N
452?;2B2N36B:C2B2?D2B2
N4 ,- , 1
2D2D=29;2B252?G2DED6AE9N52?N
A229A252=:?D2C2?N6=6B6?86?82=2:A6BE3292?646A2D2?:2H2 36B2A2
A2296=6B6?86?82=2:A6BE3292?646A2D2?A252=:?D2C2?N:2H2 36B2A2
6?EBEDA6?52A2D?52D6B2CE86B22A2296=6B6?8A252=:?D2C2?N 52?A252=:?D2C2?N
A2H2?852A2D?52C:AE=2?52B:A6B4322?:?: A
B C
Kelereng
Papan lintasan Tumpuan
Papan lintasan
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105
Tes Kompetensi Fisika Semester 1
0 0 12 4 ,5 ,. ,1. 1 , , . 22 1 , :6?C:82H2252=29
2 01010-1
N
5 01010-1
N
3 0101 0-1
N
6 01010-1 4 01
01
N
0-1
N
.C292C6D:2AC2DE2?G2DE6:=::5:6?C:C22 56?82?5:6?C:
2 6?6B8::?6D: 5 6?6B8:AD6?C:2=
3 52H2 6 82H2
4 D62?2? E2F6DB2C:?82C:?8C2DE2?52?C2DE2?C2DE
C22=2:?C2=:?8D682=EBEC ,6=:C:965E2F6DB D6BC63ED252=29
2
C2DE2? 5 C2DE2?
3 C2DE2? 6
C2DE2?
4 C2DE2? E2F6DB
52? C2DEC22=2:?636?DECE5ED
J +6CE=D2?F6DB636?DECE5EDJD6B9252A F6DB
:2F6DB F6DB
252=29 2
5 3
6 4
6D6=:D:2?2=2DEEBA6?882B:C;2?82CB?852? :B6D6BC6BEAC642B236BDEBEDDEBED252=29
2 52? 3 52?
4 5
52?
6 52? 252A6?8EEB2?A2?;2?836?525:A6B=6992C:=
A6?8EEB2? 2?H2?H22?82A6?D:?892C:= A6?8EEB2?D6BC63ED252=29
2 5E2 5 =:2
3 D:82 6 6?2
4 6A2D =E:?:EH2?82CC2?H2852?F=E6?H24
6:=::2CC2;6?:C 2
8
4
5
8
4 3
8
4
6
8
4 4
8
4
,63E293:=36B86B2632B2D56?82?646A2D2? CC6=2256D: 6E5:2?36?5236B86B2
632=:6D:EB56?82?646A2D2?
CC6=2256D: 646A2D2?B2D2B2D23:=252=29M
2
C 5
C
3
C 6
C
4
C 2B2H2?85:D6AE936?52C6=22C252=29
2 5
3 6
4 ,6C6B2?86?86?52B2:3:=56?82?A6B46A2D2?D6D2A
C ,6D6=2936B;2=2?
C3:=:DE6?6AE9;2B2
646A2D2?2G2=3:=:DE252=29 2
C
5
C 3
C
6
C 4
C
,63E293:=52B:62522?5:29:?88236B86B2 56?82?646A2D2?
C63EDE92?G2DEC
2B2H2?85:D6AE93:=252=29 2
5 3
6 4
,63E29 3:= 6:=:: 646A2D2? 2G2=
C 6?52A2DA6B=232D2?D6D2A
C
3:=D6BC63ED 22?36B96?D:C6D6=296?6AE9;2B2
2 5
3 6
4 ,63E2936?525:D6322?F6BD:2=62D2C56?82?
646A2D2?2G2=
C 6D:?88:2?36?52C6D6=29C 52B:A6?6322?252=29
C
2 5
3 6
4 :2?D2B2A6B?H2D22?36B:EDH2?8A2=:?8D6A2DE?DE
C63E2936?52;2DE93632C252=29 2 A6B46A2D2?D6D2A646A2D2?D6D2A
3 A6B46A2D2?36BD2329646A2D2?D6D2A 4 A6B46A2D2?D6D2A646A2D2?36BD2329
5 A6B46A2D2?36BD2329646A2D2?36BD2329 6 A6B46A2D2?52?646A2D2?36BEB2?8
6B:ED252=298B27:646A2D2?+D6B9252AG2DE 52B:36?52H2?836B86B2=EBEC
Tes Kompetensi Fisika
Semester 1
8 4
2 6 8
ts vms
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106
Mudah dan Aktif Belajar Fisika untuk Kelas X
,63E2936?5256?82?2CC2?H25:82?DE?856?82? C6ED2CD2=:6E5:2?D2=:5:D2B:62D2C56?82?A6B
46A2D2?D6D2A :2A6B46A2D2?8B2F:D2C:252=29
C D682?82?D2=:252=29
2 5 N
3 6 N
4
N 6B92D:2?8232B36B:ED
252=292DB=H2?8C2?82D=:4:? 2CC236?5252? 2C:?82C:?8852?8 :236?525:=6A2C
D682?82?D2=: 52?
2C:?82C:?8252=29 2
52?
5
52? 3
52?
6
52? 4 52?
,6C6B2?856?82?2CC285:D:32?85:52=2=:7D H2?8C652?86=E?4EB632G2956?82?646A2D2?
D6D2A
C :2
C 36B2DB2?8:DE252=29
2 5
3 6
4
v
t 2
1
6?5256?82?2CC2836B86B256?82?6=2;E2? ;2 2H2H2?85:A6B=E2?282B36?52:DE
36B96?D:A252;2B252B:D6A2DC6E=2252=29 2 36B=2G2?2?56?82?86B236?52
3 C62B2956?82?86B236?52 4 36B=2G2?2?56?82?86B236?52
5 C62B2956?82?86B236?52 6
C62B2956?82?86B236?52
,63E2936?5256?82?2CC28D6B=6D2A2523:52?8 52D2B 6?52 D6BC63ED 5:36B: 82H2
H2?8
636?DECE5EDJD6B9252A3:52?86?52D2B 2H2 ?B2=H2?8366B;2A25236?52:DE252=29
2 5
3 6
4 6B92D:2?8232B36B:ED
232BD6BC63ED6?E?;E2?8B27:646A2D2?D6B 9252AG2DE52B:5E23E2986B236?52H2?82CC2?H2
52? 65E236?526?52A2D82H2H2?8C22
C69:?8826?52A2D2?A6B46A2D2? 52?
2B: 8B27:52A2D5:C:AE=2?329G2
2 52?
3 52?
4 52?
5 52?
6 52?
A B
T
1
T
2
T
2
K
,6B2?8?6=2H2?6?H636B2?8:CE?82:6?88E?22? A6B29E52HE?8 6B29E52HE?8C6=2=E5:2B292?D682
=EBECD6B9252A2B292BEC2:B56?82?646A2D2?
C :2646A2D2?2=:B2?2:B
C9:DE?8=29646A2D2?
DD2=A6B29E52?2B29?H252=26=:?D2C:CE?82: ,63E2936?525:=6A2C2?D2?A2646A2D2?2G2=52B:
A6C2G2DH2?8C652?836B86B256?82?6=2;E2?D6D2A :2D:52252A6?82BE92?8:?;6=2C2?=293282:2?2
36?DE=:?D2C2?36?52D6BC63ED ,63E2936?52H2?82CC2?H2836B86B2C642B2
36B2DEB2?52=2=:?D2C2?6=:?82B56?82?646A2D2? C :2;2B:;2B:=:?82B2?:DE36B2A22982H2
82H2C6?DB:A6D2=?H2 6?82A229B2?8H2?8C652?86?2::A6B2:?2?
?D2?82?D:?8D:52D6BA6?D2=6=E2B=:?D2C2??H2 ,63E2932DE56?82?2CC2
85::2D56?82?D2=:52?
5:AED2BC69:?882=:?D2C2??H236B36?DE=:?82B2? F6BD:2=56?82?;2B:;2B: :2646A2D2?CE5ED
32DEB25
C52?
C D6?DE2?=29D682?82?D2=:
A252C22D32DE5:D:D:D6BD:?88: 4 .1 ,5 ,21, ,1. 1
Di unduh dari : Bukupaket.com
A. Cahaya B. Pemantulan
Cahaya C. Pembiasan
Cahaya D. Alat-Alat Optik
Cahaya dan Optika
,5C9181A9=1DB91C941;1;15A18C5A51B41A93181H1 541 254149B5;599741411CC5A981C;1A51141H13181H1 181H1
:D71H17=5=2D1C41411C=5981C21H171414935A=9 D7;9415A18=5=5A81C9;1;131B9?141=?291C1D
B5541=?C?A 131B9?141=?2941B5541=?C?A=5AD1;1B52D18 35A=935=2D7H17497D1;1575=D49DCD;=5981C1D9C1B
49 251;17 =?29 1C1D B5541 =?C?A 571 =5981C ;131 B9? 575=D49411C25A25?;25A85C91C1D=5418DD9;541A1119
45711=1 141;131B9?C5A:1495=1CD13181H1B58977141411C
=5981C21H17125412541H1725A14149451H1 11C;1841 =57945C969;1B9B961CB961C21H17114135A=9;131B9?
,51935A=935=2D725A41B1A;125CD;H11414D1:59B35A=9 19H1H19CD35A=941C1A4135A=935;D7 11C;18;54D135A=9
99=55ADB;13181H11719=11B961CB961C21H171H1 41411C=55CD;1:1F1215AC1H115AC1H11C5AB52DC
411=21299 58;1A519CD51:1A918212994571219;
107
• menganalisis alat-alat optik secara kualitatif dan kuantitatif;
• menerapkan alat-alat optik dalam kehidupan sehari-hari.
Setelah mempelajari bab ini, Anda harus mampu:
menerapkan prinsip kerja alat-alat optik.
Hasil yang harus Anda capai:
Pengemudi memanfaatkan pemantulan cahaya pada cermin cembung kaca spion.
Bab
6
Sumber:
Dokumentasi Penerbit
Di unduh dari : Bukupaket.com
108
Mudah dan Aktif Belajar Fisika untuk Kelas X
A. Cahaya