3 ms·As a rule of thumb, if you need to move a horse-like weight at horse-like speeds, one horsepower will do.by IvyMike 13y agoAs a rule of thumb, if you need to move a horse-like weight at horse-like speeds, one horsepower will do.tocomment 13y agoWhy are most law mowers 5 hp?WayneDB 13y agoProbably because the horses are used for moving the blade more than the mower.