Instructions: Given a scientific passage and an answer, generate a question for the given answer.
Input: Passage: Some machines change the direction of the force applied by the user. They may or may not also change the strength of the force or the distance over which the force is applied. Two examples of machines that work this way are the claw ends of hammers and flagpole pulleys. You can see in the Figure below how each of these machines works. In both cases, the direction of the force applied by the user is reversed by the machine. Answer: direction of force
Output:
Claw ends of hammers and flagpole pulleys are examples of simple machines that reverse what?