B. Complete the sentences below by writing the missing word.
6. makes our work easier and faster.
7. is a straight or bent bar resting on a pivot to help to push, pull, and lift objects
8. consists of a wheel with trench rim in which pulled rope or chain can run to change the direction, and thereby lift a load.
9. is a machine consisting of a wheel attached to a smaller axle so that these two parts rotated together. da u of the correct answer​