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Across
  1. 2. surfaces with oil,grease or graphite
  2. 4. irregularity of surfaces
  3. 6. spherical or cylindrical object
  4. 7. SI unit of force
  5. 8. the force opposing the object in motion
Down
  1. 1. the resistance an object encounters when it slides over a surface
  2. 3. rounded in the front and narrow at the back
  3. 5. fluid friction
  4. 8. push or a pull