Canal boat, as described by Galileo:
Canal boat, as described by Galileo:
“A stone dropped in the ship will fall at the same point, is the ship is fixed or moving, a candle flame will rise straight up in either case…etc.” “Dilalogue concerning the two world systems” 1604
and most importantly, the velocity of a stone thrown in the boat v, as seen from the shore, is added (or subtracted from the velocity of the boat: v’ = v + V