1) Sound is the kind of  a) work b) energy c) force d) none 2) vibration is a) visible b) invisible  c) can both (a) and (b)  d) non 3) sound can not be produce without vibrations a) true b) false

Papan Peringkat

Gaya visual

Pilihan

Berganti templat

Pulihkan simpan otomatis: ?