What type of motion involves cutting only in one direction, such as with hacksaws?

The correct answer is reciprocating motion, which is characterized by a back-and-forth motion along a straight line. In the context of cutting tools like hacksaws, reciprocating motion allows the blade to move forward to make a cut and then retract to start the next cut. This movement is essential for effective cutting of materials, as it provides the necessary force in one direction while also creating an efficient cycle of motion for creating successive cuts.

Hacksaws are specifically designed to exploit this type of motion, making them effective for cutting through different materials. The nature of reciprocating motion helps to maintain a consistent cutting action, ensuring that the blade remains effective in making precise cuts.

Other options like circular motion and rotary motion describe actions that rotate around a fixed point but do not apply to hacksaws since they do not cut in a circular path. Linear motion refers to movement in a straight line, but it does not encompass the back-and-forth aspect inherent in the reciprocating motion of a hacksaw. The unique characteristics of reciprocating motion enable tools like hacksaws to function effectively in specific cutting applications.