I have a typical cable reel, constructed of a central hub that the cable winds around and two end flanges of larger diameter. If I place the reel upright on its flanges on the floor, and unwind some of the cable in such a way that the cable comes off the underside of the hub towards me, and then pull on the cable, which way will the reel roll? That is, will it try to roll towards me (winding up the cable as I pull), or will it roll away from me (unwinding the cable)? Assume the friction between the floor and the flanges of the reel is sufficiently high to prevent the reel from just spinning in place.
I have found that about half the people get it right and half wrong. What do you think?