How to create 3D effect of throwing objects from 1st person viewpoint

I am building a simple flash game which involves throwing objects at a moving target. The game will be viewed from a first person perspective and the idea is that the horizontal postion is determined by the mouse position and the length / power of the throw is based on hte length of the mouse click.

The objects will appear from the bottom of the screen and shrink in size adn move up the screen to simulate their trajectory but I am having difficulty making it look right and also making it adaptable for different strengths

Any ideas?