In 1 second, a train travels 20 meters north.  The displacement of the train at the end of stated time is 20 m/s

20 m/s north

20 m north

20 m

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.