The opening sentence of a recent piece by Laura Spinney in The Guardian:
Isaac Newton apocryphally discovered his second law – the one about gravity – after an apple fell on his head.
Newton’s second law of motion is F = ma. His gravity law – that of universal gravitation – is Fgr = G(m1m2)/R2.
This confusion isn’t a big deal by itself. But as an introduction to a popular science piece, it doesn’t look good at all.