A spool of inner radius $r$ and outer radius $R$ ($r < R$) rests on a rough horizontal floor. A thread is pulled **horizontally** off the **bottom** of the inner shaft. The spool:

Take torque about the **contact point** (instantaneous axis). Pull force acts horizontally at height $r$ above the floor, so its moment arm about the contact point is $r$ — the torque rotates the spool such that it rolls TOWARD the puller, taking up the thread. Counter-intuitive but well-tested JEE Adv result. (Pulling above the centre would reverse direction.)