Final answer:
Mechanics put a length of pipe over the handle of a wrench to increase leverage and the resulting torque, which can make it easier to loosen a very tight bolt. However, this method can also be risky as it might break the bolt due to the excessive torque applied.
Step-by-step explanation:
Mechanics often use a technique where they put a length of pipe over the handle of a wrench to remove a very tight bolt. This practice is based on the principle of leverage, which is a fundamental concept in physics. By using a pipe to extend the handle of the wrench, the mechanic increases the torque that can be applied to the bolt. Torque is the force that causes an object to rotate, which in this context helps in loosening the bolt.
With greater length, a longer moment arm is created; this means that the same amount of force applied at a greater distance from the pivot point (in this case, the bolt) results in a larger torque. However, this method can also be hazardous, as the increased torque can also exceed the strength of the bolt, potentially causing it to break.