Work and energy

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Across
  1. 3. opposes motion, generates heat
  2. 6. ratio of the adjacent to the hypotenuse
  3. 8. a right angle
Down
  1. 1. caused by or related to gravity
  2. 2. ratio of useful work to total input energy
  3. 4. this is the unit of work
  4. 5. rate at which work is done
  5. 7. product of the force and distance moved in the direction of the force