400
You are on your bike showing off. You are doing the old, "look ma, no hands" trick. However, unbeknownst to you (but unbeknownst to your audience) there is a very large and very sturdy downed tree in your path. This is most likely what will happen.
What is I will be flung off my bike in a straight trajectory when my bike (which is in motion) is quickly put to rest by the downed log. I however, never made contact with the log and will continue in this embarrassing motion that the bike would have been a part of...until gravity or another force puts me out of my misery.