we use a wrench to turn nuts on bolts because they require less force . consider a hexagonal nut of 1 cm in diameter. we can tighten this nut with one of two wrenches , wrench A with lever arm 10 cm and wrench B with lever arm 20 cm. both wrenches have a very small mass , so you may neglect their masses in this problem. what is the ratio of the total work it would take to tighten the nut one full turn with wrench A to the total work it would take with wrench B.