Free-body diagrams are a pretty useful tool and I wanted to devote a little time to talking about the ones I created for the Danny Macaskill video.  In particular look at the short clip starting at 50 seconds:

I had originally thought he pushed down with his hands and feet but in viewing the video I see I was wrong.  What he does is pull the front wheel up, then push himself up with his feet.  I realized this when I was doing a video analysis, which I’ll post in a bit.

To create the free-body diagram (FBD) I made a few assumptions and simplifications.  I ignored all horizontal forces and just focused on vertical forces.  I also assumed the rider and bike have similar masses and therefore similar weights.  I don’t have numbers, but if the bike was too much heavier than him it would be hard to pull…