Jawabanmu

2014-08-26T15:06:43+07:00
Usaha (W) = Gaya x Perpindahan
                 = 15 x 4 = 60 Joule
2014-08-26T15:12:39+07:00
Rumus W = F x s
maka W = 15N x 4000m = 60000 J