Two objects, a block and a spool, are each pulled across a level, frictionless surface by a string. The block and the spool have the same inertia. The string pulling the block is tied to a small hook at the center of the front face of the block. The string pulling the spool is wrapped many times around the spool and may unwind as it is pulled. The strings start pulling with the same constant force at the same instant. (Make the approximation that the strings and the hook are massless.)