Q: Given a scientific passage and an answer, generate a question for the given answer.
Passage: A machine is any device that makes work easier by changing a force. When you use a machine, you apply force to the machine. This force is called the input force. The machine, in turn, applies force to an object. This force is called the output force. Recall that work equals force multiplied by distance:. Answer: changing a force
A:
A machine is any device that makes work easier by doing what?