I am currently working on a top down zombie killing car racing game and suddenly I felt need of bouncing off obstacles on the road. After trying for sometime, I found this solution. Sharing it with you all through this video.
1. Add bullet behavior to obstacles
2. Set speed 0 and bounce option to yes
3. now on collision set speed of obstacle to 450 (or any number)
4. set angle of motion to hitting object.angle in degrees
5. Reduce speed to object till it stops.
Have created video to show the effect and code.