bantu no 19 dan 20. pakai jalan

19.
diket :
n = 2
t = 8 s
l = 16 m
ditanya v?
jwb :
f = n/t = 2/8 = 1/4 hz
lamda = l/n = 16/2 = 8 m
v = f x lamda
= 1/4 x 8 =2 m/s (a)