Supiyanto Kelas X Evaluasi Bab 3 Nomor 8

Roda A dan roda B bersinggungan luar. Jari-jari roda A adalah 2 cm dan tiap menit roda A berputar 20 kali, sedangkan roda B tiap menit berputar 13 kali. Jari-jari roda B adalah …

A. 1,5 cm D. 3,5 cm
B. 2,5 cm E. 4 cm
C. 3 cm

Penyelesaian

Perbandingan kecepatan linear A dan B

{{\text{v}}_{\text{A}}}={{\text{v}}_{\text{B}}}

{{\text{ }\!\!\omega\!\!\text{ }}_{\text{A}}}.{{\text{R}}_{\text{A}}}={{\text{ }\!\!\omega\!\!\text{ }}_{\text{B}}}.{{\text{R}}_{\text{B}}}

{{\text{R}}_{\text{B}}}=\frac{{{\text{ }\!\!\omega\!\!\text{ }}_{\text{A}}}}{{{\text{ }\!\!\omega\!\!\text{ }}_{\text{B}}}}\times {{\text{R}}_{\text{A}}}=\frac{20\text{ }\!\!~\!\!\text{ putaran}/\text{menit}}{13\text{ }\!\!~\!\!\text{ putaran}/\text{menit}}\times 2\text{ }\!\!~\!\!\text{ cm}=3,08\text{ }\!\!~\!\!\text{ cm}

 

Jawaban C

Supiyanto. 2006. FISIKA UNTUK SMA KELAS X. Jakarta: Phiβeta.

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