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Homework #3 solutions
•Question 3   Newton concluded that some force had to act on the moon because
 
a.the moon moved at a constant velocity.  
•b.a force is needed to pull the moon outward.  
•c.a force is needed to pull the moon away from straight-line motion.  
•d.a force is needed to keep the moon in motion.  
•e.all of the above.