GETARAN

• Getaran adalah gerak bolak balik suatu benda secara periodik melalui titik setimbangnya.
• Menurut benda yang bergetar dan cara bergetarnya, getaran dibedakan:
• Getaran ayunan, contohnya bandul jam
• Getaran selaras, contohnya pada pegas
• Getaran tunggal, contohnya pada alat musik kulintang

• Alat dalam kehidupan sehari-hari yang memanfaatkan getaran:
• Jam dinding, bagian yang bergetar bandul jam, jenis getarannya ayunan
• Gong, bagian yang bergetar badan gong, jenis getarannya selaras
• Gitar, bagian yang bergetar senarnya (saat dipetik), jenis getarannya tunggal
•  Ayunan, yang bergetar tali ayunan, jenis getaran ayunan
• Biola, yang bergetar senarnya, jenis getarannya tunggal, dll

 

Earthquakes

Summary:

~ Earthquakes, or seismic tremors occur when energy stored within the Earth suddenly releases.

~ The energy stored is usually in the form of strain in rocks. This energy is transmitted to the surface of the earth by earthquake waves.

~ The centre where the earthquake energy release is called focus.

~ Epicentre is the highest energy of seismic waves occur.

~ There are two kinds of earthquakes : tectonic and volcanic.

~ Tectonic earthquakes are caused by the sudden release of energy stored within the rocks a long a fault. The released energy is produced by the strain on the rocks due to movement within Earth.

~ Volcanic earthquakes occur near active volcanoes but have the same fault slip (or landslide) mechanism as tectonic earthquakes.