Final answer:
Using a length of pipe over a wrench handle increases leverage and torque, which helps to loosen tight bolts, but it can be hazardous as it may break the bolt.
Step-by-step explanation:
Mechanics sometimes place a length of pipe over the handle of a wrench to remove a very tight bolt because doing so increases the leverage available to turn the wrench. By increasing the length of the lever arm (the wrench handle), the mechanic can apply the same force but generate more torque due to the longer moment arm. This mechanical advantage helps to loosen the bolt without needing to apply more force. It is important to be cautious with this technique since introducing too much torque can break the bolt, rendering it ineffective and possibly damaging the equipment.
By increasing the distance from the center of the bolt to the point where force is applied, the torque on the bolt is increased. This helps overcome the resistance caused by the tightness of the bolt, making it easier to loosen.
However, using a breaker bar can be hazardous. If too much force is applied, the bolt may break. Additionally, if the mechanic or anyone nearby is not careful, the sudden release of force from the bolt breaking can cause injury.