Mechanics sometimes put a length of pipe over the handle of a wrench when trying to remove a very tight bolt. how does this make it easier for the mechanic to remove the bolt?

Torque =  force * distance

it is easier remove when the wrench is move in anticlockwise direction to loosen it.

Explanation:

putting a length of pipe over the handle of a wrench when trying to remove a very tight bolt means additional force is needed to be applied to the bolt to make it losen.

Applying pipe increase the force applied which increases the distance to applied the force and consequently increase the torque.

mostly, most bolt are tighten in a clockwise direction, therefore to loose then, the wrench will move on a anti clockwise direction.

54 degrees incident angle = reflected angle

angle is from normal turned to line of ray