tolong ya.. nomor 7 & 8 aja.. pakai caranya makasih^^

7. Dik =
t = 5 s
n = 10
v = 18 m/s
Dit = λ?
Penyelesaian =
- f = n / t
= 10 / 5 s
= 2 Hz
- v = λ . f
λ = v / f
= 18 m/s / 2 Hz
= 9 m
Jawaban : A
8. Dik =
f = 2,5 kHz ⇒ 2500 Hz
λ. = 0,136 m
Dit = v?
Penyelesaian =
v =λ.f
= 0,136 x 2500
= 340 m/s
Jawaban : C

Semoga membantu.

Nomor 7
λ = vT
   = vt / n
   = (18 m/s)(5 s) / 10 = 9 m

Nomor 8
v = λf
   = (0,136 m)(2500 Hz) = 340 m/s