Capturing motion

So yesterday morning I walked around DC taking pictures for my photography class.  The goal was to capture motion and to use shutter speed and aperture to compose my photographs.  I'm telling you this photography thing is not as easy at it seems.  Here's a couple of photos for your viewing pleasure.  Let me know what you think...I need feedback.

This one is from the ice rink near the Smithsonian -- it's a little overexposed. 

Tell you the truth I wasn't too happy with what I took on Saturday, so I pulled one I took in NYC over the summer.  It's post processed but the "blur" effect came from adjusting my shutter speed. 

Maybe it's because NYC is better city to photograph...that's for a different blog entry.