It is a win but it's very hard. Use a tablebase to show you the win. The position you show takes 32 moves to win (with best play from both sides.)
Rook+Pawn vs Queen

The Shredder tablebase is viewable at: http://www.shredderchess.com/online-chess/online-databases/endgame-database.html
Hi everyone! I was playing this game with a Rook+Pawn vs Queen end game. I played like 30 moves but wasn't able force a win on the rook side, I was playing black, with the queen and in the end I offered a draw and white gladly accepted. I am wondering whether this position was a win-able from black's point of view. Can someone please tell me this and also how to win in such position. I tried so much but couldn't. Thank you.