Menghitung Massa Bumi Hukum Gravitasi Universal Newton

38 Mudah dan Aktif Belajar Fisika untuk Kelas XI -.1:0- 0-:9-5:39-5:3.1=9--730-:730581?-77-:?1=5-4-0- 6-=-79 59-:-7-4?5?574-=05?19-?7-:-3-=7-?910-:3=-A5?-505 ?19-??1=1.?-9-01:3-::;8 3 571?-45 73 73 99 ---?-4-=50--?0545?:3.1=0--=7-:B-7?10-=9518-9- ?-4: -=-7-:?-=-950-:-?-4-=5-0-8-4H 9145:33- 9-- -?-4-=5 -0-8-4 = = 9 H 9 73 H = H 73

2. Kuat Medan Gravitasi

19- .1:0- 05 175?-= 1=97--: 95 -7-: 051:3-=45 ;814 910-: 3=-A5?-5 95 145:33- 91958575 3-D- .1=-? D-:3 .1-=:D- 1.-:05:3 01:3-: 1=1-?-: 3=-A5?-5 05 ?19-? ?1=1.? 1=1-?-: 3=-A5?-59505-??19-?-7-:19-75:7158657-6-=-7-:?-=--? 95 71 ?19-? ?1=1.? 19-75: 6-4 =?5:D- 19-75: 6-4 81?-7 1.-4 .1:0- 0-=5 -? 95 19-75: 7158 3-D- 3=-A5?-5 95 D-:3 05-8-95;814.1:0-?1=1.? 91::677-:1=1-?-:3=-A5?-5 05 .1.1=-- ?19-? 1:=? 917-:57- 1B?;: 3-D- .1=-? 3-D- 3=-A5?-5 1.-4 .1:0- 9191:45 1=-9--: 01:3-: 051.? 1=1-?-: 3=-A5?-5 D-:3 63- 91=-7-: 3-D- 1= -?-: 9-- D-:3 058-77-: 95 ?1=4-0- 1?5- .1:0- 0-: 051.? 910-: 3=-A5?-5 95 57- 9-- 95 0-: 9-- 1.-4 .1:0- D-:3 .1=-0- 05 1=97--:95 .1:0-.1=9-- ?1=1.?-7-:91:0--?7-:3-D- 3=-A5?-5 D-:3 .1-=:D- 145:33- -7-: 051=;814 G 1?1=-:3-: 7-? 910-: 3=-A5?-5 9 7;:?-:?- 3=-A5?-5 :5A1=-8 9 73 6-=-7 .1:0- ?1=4-0- -? 95 9 .+ 5 ?1=1.? -0-8-4 1=-9--: D-:3 91:D-?-7-: .1-= 1=1-?-: 3=-A5?-5 95 D-:3 05-8-95 ;814 -? .1:0- D-:3 .1=6-=-7 0-=5 -? 95 0-: 91:0--? 7-? 910-: 3=-A5?-5 3 0-: 91=-7-:7;:?-:?-0-:.1-=-:.1=.-:05:3?1=.-857 01:3-: 6-=-7 -? .1:0- ?1=4-0- -? 95 -05 19-75: 6-4 81?-7 -? .1:0- 19-75: 7158 1=1-?-: 3=-A5?-5 D-:3 05-8-95 -? .1:0- 58-51=1-?-:=-A5?-505 1=.-3-519-? -0 ?.+?-=- =11:8-:0 ?;74;89 =18 1B,;=7 1:A1= -:=-:5; 4-?85?5B- .-0+ .20 1.1=3-:?:3-:58-51=1-?-: =-A5?-501:3-:1?5:335-: 0++ Contoh 2.8 Sumber: Physics for Scientists and Engineers with Modern Physics, 2000 Sumber: Physics for Scientists and Engineers with Modern Physics, 2000 Gaya 39 A B 50 cm x g A P g 2 m A = 4 kg m B = 9 kg Pembahasan Soal Perbandingan antara jari-jari sebuah planet R p dan jari-jari Bumi R b adalah 2 : 1, dan perbandingan massanya 10 : 1. Jika berat Butet di Bumi 100 N, di planet tersebut beratnya menjadi .... a. 100 N b. 200 N c. 250 N d. 400 N e. 500 N Soal UMPTN Tahun 1990 Pembahasan: Percepatan gravitasi g = M R 2 p b g g = p b p b M R R M 2 = 2 1 10 2 1 = 2,5 g p = 2,5 g b maka w p = 2,5 w b w = 2,5 100 N = 250 N Jawaban: c 5-8:D-81?-7?5?57 0-=5.1:0--0-8-4 3-=7-?910-:3=-A5?-505?5?57-9- 01:3-::;89-7- G G 9 -05?5?574-=05?19-?7-:-0-6-=-7 90-=5.1:0- 11=?5 4-8:D- 3-D- 3=-A5?-5 1=1-?-: 3=-A5?-5 63- 91=-7-: .1-=-:A17?;= -05.1-==18?-:1=1-?-:3=-A5?-5D-:3.171=6--0- 1.-4?5?57-75.-?910-:3=-A5?-5D-:3054-587-:;8140-.-4.1:0- .1=9-- 0-: 4-= 0545?:3 8- 1-=- A17?;= 1=4-?57-: . 1-==18?-:710-1=1-?-:3=-A5?-5?1=1.?-0-8-4 ; G 1?1=-:3-: g 0-: g m 1 r 1 g 1 g g 2 m 2 r 2 Gambar 2.14 Resultan percepatan gravitasi -.-4.1:0-.1=9--730-:73 1=0--?1.-4?5?57 D-:3.1=6-=-7-9- 0-=5.1:0-0-:.1:0- D-5?9D-:3919.1:?70?F11=?5-0-3-9.-= 57- 7;:?-:?-3=-A5?-5 H G 9 73 ?1:?7-:7-?910-:3=-A5?-505?5?57 3 571?-45 9 73 73 73 9 73 9 -?910-:3=-A5?-5051=;8140-=51=-9--: ; ; H G 73 -057-?910-:3=-A5?-5H G 73 m 1 = 5 kg m 1 = 15 kg 5 m 5 m g 1 g 60° g 2 O Contoh 2.9