9
Pengukuran dan Besaran
85G4;BF4BD84CC4A=4A:AK4
6?854DAK4
674AFA::AK46 7GGD78A:4AEF4D78A:4A8F74C4EF4A
6+8AFG4AHB?G8BF474A
8F74C4EF4AAK4 4A=4A:
6F:44A:4C8AFA:
?854D 67G44A:4C8AFA:
FA:: 67G44A:4C8AFA: 8AG?E4AHB?G8BF4BD84C;4DGE7G44A:4C8AFA:E8EG478A:4A4A:4
C8AFA:K4A:F8D86?K4FG?854D74AFA::BF4 +TT
6T
6T66
7FG?E 6
V V
p l
t p
l t
0, 05 0, 05
0, 05 10, 2
3,1 1, 4
V
T
T6 47;4E?C8D;FGA:4AHB?G8BF4BD84C7?4CBD4AE854:4
6 7FG?E78A:4A4A:4C8AFA:
4. Aspek-Aspek Pengukuran
a. Kesalahan dalam Pengukuran
8A:GGD4A8DGC44A54:4AC8AFA:74DE85G4;CDBE8E8EC8D8A EC8D8AK4A:54474?4;8EC8D8AK4A:8?8E4?4;4A ---
E886?GA:A---474?4;8E4?4;4AK4A:F8D=478F48?4G4A 8:4F4A8EC8D8A8E4?4;4A74?48?4G4AC8A:GGD4A474?4;
E8EG4FGK4A:F7474C4F7;A74D474GGAK48F48?4G4A C8A:GGD4A 58DG?4A: EG4FG 58E4D4A ;4E? K4A: 774C4F4A 58D5874
I4?4GCGA4?4FGGDK4A:7:GA44AE44 ,82.4889,398
8E4?4;4AEEF84FE74C4F7E85454AB?8;8E4?4;4A74?4C8A8D44A 4?5D4EAEFDG8AGGD8E4?4;4A454FC8A:4DG;6G464?A:GA:4A
4F4G4?4FF7474C4F588D=4E864D4BAEEF8AE8;A::4;4E?C8A:GGD4A F74E4478A:4AA?4K4A:F8DFG?E74?4?F8D4FGDC854A7A:
8E4?4;4AEEF84FE74C4F8A=47E4A:4FDGFA74;4AK474C4F 8C8D86?8E4?4;4AF8DE85GF78A:4AC8A:GGD4AE854GA:A
4D4 C4?A: G74; GAFG 8A:GD4A: 8E4?4;4A EEF84FE 474?4; 8A:;A74DC8AK8545AK4E864D48E8?GDG;4AK4FG78A:4A8AKGEGA
AEFDG8AC8A:GGD4AE864D458A4D74A8A:;A74DE854AK4GA: A8E4?4;4A454FC8A:4DG;94FBD?A:GA:4A
,82.41 8E4?4;4A46474C4FF8D=478F4EEF84F4C8D6B544AEG74;
7C8AG;E864D458A4D4E4AK48E4?4;4A464F8D=474D8A44?4FK4A: GD4A:E8AEF9474AK4:4A::G4A?G4DCDBE8EEF4FEF4C8D;FGA:4A4F4G
---C474B5=8C8A:GGD4AE4?AK4C8DG44A4E4D74DEG4FGE4C8? 74C4F85G4FC8A:GGD4A8F854?4AE85G4;58A7458D587474DEG4FG
FF 78A:4A FF ?4A 4F4G ?A:GA:4A F8C4F A74 8?4G4A C8A:GGD4A E8C8DFF5G?AK4:8F4D4AB?8;E85G4;8EAK4A:E874A:
58DBC8D4E74C4F8AK85454A 8E4?4;4A 464 ,AFG 8A:;A74D C8A:4DG;8E4?4;4A464C4744EGEE8C8DFFG44E84A54AK4
7?4G4AC8A:GGD4AE84A54;4E?AK48E4?4;4A464A74C4F
• pengukuran
• ketidakpastian
• ketelitian alat
• skala utama
• skala nonius
Kata Kunci
Sebutkan contoh-contoh kesalahan dalam pengukuran yang
termasuk kesalahan sistematis dan kesalahan acak.
Tantangan
untuk Anda Contoh
1.3
10
Mudah dan Aktif Belajar Fisika untuk Kelas X
7C8DD44A58E4DAK48?4?G4A4?EEEF4FEF4K4FG78A:4A8C8D54AK4 4F4G8A:G?4A:G?4A:C8A:GGD4A78A:4A8A:G54;58D54:4C4D48F8D
C474C8D6B544AF8DE85GF b.
Presisi dan Akurasi
8F8C4F4A 4F4G 4GD4E 8AK4F44A 8784F4A ;4E? C8A:GGD4A 78A:4A;4E?E858A4DAK4I4?4GCGAA?4K4A:E858A4DAK474?4?F8D4FGD
8DGC44AC8A784F4AK4A:74A::4C58A4D 8D;4F4A37E4?AK47?4G4AC8A:GGD4AEG4FG
58E4D4A74DE85G4;B5=88A::GA44A7G4=8AE4?4FK4FG4?4F74A 4?4F3
474?4;A?4E858A4DAK458E4D4A58A74F8DE85GF4F4;4E? C8A:GGD4A8A::GA44A4?4F?85;8A784FA?4E858A4DAK43
74DC474C8A:GGD4A8A::GA44A4?4F4C4F74F44A54;I44?4F 8?4GD4E?85;5474DC4744?4F8A:GGD4A74F44A
4GD4F=48?8E4?4;4AK4A:86? D8EE8DGC44ACDBE8EC8A:GGD4AK4A:8?8E4?4;4A464
E886? GA:A 37 8DGC44A E854D4A 74F4 74D C8A:GGD4A58DG?4A:EG4FG58E4D4A74DE85G4;B5=88A::GA44A7G4
=8AE4?4FK4FG4?4F74A4?4F 8DGC44AE854D4A74F474DC8A:GGD
4A8A::GA44A4?4F74A 8DGC44AE854D4A74F474DC8A:GGD4A
8A::GA44A4?4F4D:454DF8DE85GFF8D?;4F54;I4E854D4A74F4 ;4E?C8A:GGD4A78A:4A4?4F?85;86?74DC474E854D4A74F4;4E?
C8A:GGD4A78A:4A4?4F8A:4A784A ?85;86?74DC474
4C4F74F44A54;I44?4F?85;CD8EE74DC4744?4F
Gambar 1.10
a Alat A lebih akurat daripada alat B. b Alat A lebih presisi daripada alat B
4?4F 4?4F
3
a
b
3
,70142.+23:1:29.4 85GF4A=8AE=8AE4?4FGGD8E4D4AE44C4K4A:
7GGDB?8;4?4FF8DE85GF +8AFG4A54644AK4A:7FGA=G4AB?8;=4A:4EBDBA:
C474:454D58DGF
5 6
cm 1
2 4
5 1 0
C4F5G4;D8EEFBD7;G5GA:4AE864D4E8DA?4E8F4C D8EEFBD;4E?C8A:GGD4A58DFGDGFFGDGF474?4;
+8AFG4A ;454F4A FBF4? 78A:4A 8F74C4EF4AAK4
4E?C8A:GGD4A58DG?4A:F854?8DF4E4DFBA8A: :GA44ADB8F8DF8D64F4FC474F458?58DGF
+8AFG4A54644AK4A:7FGA=G4AB?8;DB8F8D E8DGCC474:454D58DGF
4 +8AFG4A?4;;4E?C8A:GGD4AF854?8DF4EF8DE85GF
58DGF8F74C4EF4AAK4 5
3
,
1 2 20
15 10
5 45
Tes Kompetensi Subbab
A
4
8 cm 9 cm
5 5
5
30 25
0 1 2 3 4 5 6
B. Angka Penting
+ 474?4;. 04+ - -.+ 00- A:4C8AFA:F8D7D4F4E4A:4C4EF74A4A:4F4ED4A4A:4K4A:
7D4:G4AE8EG478A:4AFA:4F8F8?F4A4?4FGGDK4A:7:GA44A
11
Pengukuran dan Besaran
8F4A748A:GGDC4A=4A:E85G4;58A748A::GA44AEF4D58D E4?4?8F8DA74;4DGE85464E4?4E4C4?8F8DF8D784F
8G74AC4A=4A:EE47F4EDE854:4E8F8A:4;54:4A74AE4FG??8F8D E4?AK4C4A=4A:58A74K4A:A74GGD7FGA=G4AE8C8DFC474
37474:454DF8DE85GFF4C454;I4G=GA:58A74F8D?8F4 74AF4D44A:4674A6GA:AA7444A8AK4F44A
54;I4C4A=4A:58A74K4A:8A784F858A4D4A474?4;6A:4 F8D4;DK4A4A:4474?4;4A:4C8DD44AF4ED4A4D8A44A:4
AF74F8D5464C474E4?4EF4D8A:4A784A4A:4C8AFA:;4E? C8A:GGD4AC4A=4A:58A74F8DE85GFK4A:A74?4G4AFGF8D7D4F4E
8C4F4A:4C8AFA:
1. Aturan-Aturan Angka Penting
,AFG8A8AFG4A4A:4C8AFA:7:GA44A4FG4AE854:458DGF 4 8G44A:45G4AAB?474?4;4A:4C8AFA:
BAFB; :8A:4A7GA:8C4F4A:4C8AFA:
68A:4A7GA:F:44A:4C8AFA: 5 8G44A:4AB?K4A:F8D?8F474AF4D44A:45G4AAB?474?4;
4A:4C8AFA: BAFB;
:8A:4A7GA:8C4F4A:4C8AFA: 8A:4A7GA:?44A:4C8AFA:
6 A:4AB?7E858?4;4A4A4A:45G4AAB?F8D4EG4A:4C8AFA: 86G4?758DF4A74:4DE54I4;C4744A:4K4A:7D4:G4A
BAFB; :8A:4A7GA:?44A:4C8AFA:
:8A:4A7GA:8C4F4A:4C8AFA: 7 44A:4K4A:758D:4DE54I4;8DGC44A4A:4F4ED4A4F4G
4A:4K4A:7D4:G4A4A:4A8DGC44A4A:4C8AFA: BAFB;
64A:47D4:G4AE8;A::4;4AK48A:4A7GA:F:44A:4C8AFA: 4A:4 AB? 8F:4 C8DF44 7D4:G4A E8;A::4 ;4AK4
8A:4A7GA:F:44A:4C8AFA: 8 A:4AB?K4A:F8D?8F47E858?4;D4A:45G4AAB?54K4A:F8D?8F4
7E858?4;D4GCGA7E858?4;4A4AB478E4?5G4A4A:4C8AFA: BAFB;
:8A:4A7GA:F:44A:4C8AFA: :8A:4A7GA:7G44A:4C8AFA:
2. Operasi-Operasi dalam Angka Penting
4?44FGD4A58D;FGA:78A:4A4A:4C8AFA:K4A:;4DGE7A:4F 474?4;=G?4;4A:4C8AFA:;4E?C8D;FGA:4AF74GA:A8?85;
=G?4;4A:4C8AFA:C474;4E?C8A:GGD4A a.
Operasi Penjumlahan dan Pengurangan dengan Angka Penting
474BC8D4EC8A=G?4;4A4F4GC8A:GD4A:4A5?4A:4A5?4A:4A78A:4A 58DC87B4AC4744FGD4A4A:4C8AFA:;4E?BC8D4EC8A=G?4;4A4F4G
C8A:GD4A:4AFG;4AK45B?8;8A:4A7GA:E4FG4A:4K4A:7D4:G4A 6,786,40:32.4
4A:47D4:G4A 4A:47D4:G4A
4A:4E4FG4A:4F8D4;D7D4:G4AE8;A::4C8 AG?E4AAK48A=47
Gambar 1.11
Mistar merupakan alat ukur panjang yang memiliki angka pasti dan angka
tafsiran.
