So I made an observation that I would really like anyone who is good with mechanics to look over to see if I got the math right and didn't miss anything obvious. It's the latest post in my blog "leapingleibniz.wordpress.com" [Broken] and it involves the derivation of an equation for how much force is required to push a wheelbarrow over a curb based only on angles and the force of gravity. Specifically I am wondering if I screwed up by ignoring the normal force. My reasoning for doing so is that I wanted to find the minimum force required to maintain static equilibrium with only the applied force causing torque up over the curb without the normal force contributing, and this would the minimum force required to push the wheel up over the curb. The normal force won't apply any torque once the wheel starts moving up off the ground, but this is still bugging me... anyway, any observations would be greatly appreciated!