Jawabanmu

2014-06-20T10:52:51+07:00
W = F . cos . s
30 = 15 . cos 60 . s
30 = 15 . 1/2 . s
60/15 = s
4 m = s

:)
2014-06-20T11:00:25+07:00
W= f x cos 60x s
s= w : (f x cos 60 )
s = 30 j : ( 15x 1/2 )
s= 30 j : 7.5
s= 4 m