is the time measuring device in which periodic motion is produced by mechanical winding.

Which statement is true? a. kepler's laws apply only to the motion of earth. b. kepler's laws can be used to predict eclipses. c. kepler's laws are true for a central force that is directly proportional to distance. d. kepler's laws can be deduced from newton's laws of motion and gravity.

Awave that is traveling fast can be said to have a high a. frequency b. speed c. wavelength d. amplitude e. period f. none of these

Which of the following is a measure of the amount of light a star directly emits?               a.  luminosity    b.  intensity    c.  wavelength    d.  brightness