96
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
97
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
98
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
99
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
