An 80lb mass moving at any appreciable speed hitting you is going to suck regardless of what it is.
At a leisurely 3 mi/h, wolfram alpha gives this amusing comparison: about 0.36 times the momentum of an American football player moving at a speed of 1 m/s.
At a leisurely 3 mi/h, wolfram alpha gives this amusing comparison: about 0.36 times the momentum of an American football player moving at a speed of 1 m/s.