UN Fisika 2016 Paket 1 Nomor 14

Perhatikan gambar!

14

Massa {{m}_{1}}={{m}_{2}}=4~kg dan {{m}_{3}}={{m}_{4}}=2~kg, panjang a = 1 meter dan b = 2 meter serta massa batang penghubung diabaikan, momen inersia sistem partikel terhadap sumbu y adalah …

A.    24~~kg.{{m}^{2}} D. 56~~kg.{{m}^{2}}
B.     32~~kg.{{m}^{2}} E. 60~~kg.{{m}^{2}}
C.     34~~kg.{{m}^{2}}

Penyelesaian

Momen inersia I=m{{r}^{2}}

Momen inersia dipengaruhi oleh titik yang tegak lurus poros. Titik yang berada di poros, momen inersianya 0.

 

Momen inersia total \text{ }\!\!\Sigma\!\!\text{ }I=\text{ }\!\!\Sigma\!\!\text{ }m{{r}^{2}}

 

\text{ }\!\!\Sigma\!\!\text{ }I={{m}_{1}}r_{1}^{2}+{{m}_{2}}r_{2}^{2}+{{m}_{3}}r_{3}^{2}+{{m}_{4}}r_{4}^{2}

\text{ }\!\!\Sigma\!\!\text{ }I=4{{(2)}^{2}}+4{{\left( 1 \right)}^{2}}+2{{\left( 2 \right)}^{2}}+2{{\left( 4 \right)}^{2}}

\text{ }\!\!\Sigma\!\!\text{ }I=16+4+8+32

\text{ }\!\!\Sigma\!\!\text{ }I=60~kg.{{m}^{2}}

jawaban E

Advertisements

2 thoughts on “UN Fisika 2016 Paket 1 Nomor 14”

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s