Two pawns against one on the same wing is normally drawn: the defender keeps the rook active, trades pawns when possible, and keeps the king near the remaining pawn.
White has pawns on f3 and g4 against Black's single pawn on g5. On the same side of the board this material advantage is usually not enough, provided the defender does not drift into passivity.
Common mistakes
Kh6The king goes to the edge; White plays 2.f4 and the pawns advance with the black king shut out. Lost.
Kh7Also abandons the fight for f5 and e5; 2.f4 and White wins.
Rf1The rook goes in front of the pawns where it is passive; 2.f4! and the white pawns advance with the king, while the rook on f1 cannot check from a distance. Lost.