Rhett Allain kills me. Here you have him writing several hundreds words (with LaTeXing and diagrams) taking down the dubious physics of Ruff Ruffman, animated host of the children’s show FETCH! with Ruff Ruffman:

Ruff, if this is indeed the definition you used – I am not sure if it fits in this case. Maybe you meant momentum, although I think that is not quite right either. How about I solve this problem?

This is why God made blogs.