Nice idea, great capture of motion. Composition is good but imo it needs a bit more contrast. The shadow from on-camera flash is distracting. Can you try moving farther away from the background to see if that's better?
This is a little grainy. Beyond that, I like the shot. Perhaps a darker or black background along with a polished coin would make this image pop more and allow you get a crisper image cutting out some of the noise.
good idea. I think though I would crop out some of the top. also a different color for background. everything is close colors, kind of washes it all out. something to add contrast to your subject.