time and motion

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Across
  1. 3. distance moved in unit time.
  2. 5. a weight hung from a string.
  3. 7. that can be measured.
  4. 8. travels in a straight line.
Down
  1. 1. the time taken by a pendulum.
  2. 2. comparison of some unknown quantity with some fixed quantity.
  3. 4. a substance whose
  4. 6. it is not constant.