Science Crossword Puzzle ( Simple Machines)

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Across
  1. 2. a device that makes our work faster and easier
  2. 3. what is in center of a lever
  3. 4. a wheel with a groove and a rope in the groove
  4. 5. this is a type of screw
  5. 7. a triangular tool often made of metal, plastic
Down
  1. 1. flat sloping surface over which objects can be pushed or pull with less effort
  2. 6. an inclined plane wrapped around a cylinder