Jawabanmu

2014-04-16T21:29:38+07:00
V = λf = λ\T
2 = 15/T
T = 15/2 = 7,5s
2014-04-16T21:32:11+07:00
V = 2  m/s
λ = 5 m
v = λ x f
dimana f = 1/T
maka,
v =λ x 1/T
2 = 5 x 1/T
2T = 5
T = 5/2
T = 2,5.
maaf yaa kalo salah..