Chucking?

Please folks investigate on the Inet what causes chucking before you espouse your theory and cures. Investigation and some knowledge of physics is required so this discussion can be meaningful. Many times these types of discussions get convoluted and end up confusing. This subject is not that complicated but some how ends up that way. Also, it would be helpful to show a link supporting your theory/cure. Otherwise it could be taken as a "wise tale."