Now, three masses (m1 = 4.3 kg, m2 = 12.9 kg and m3 = 8.6) hang from three identical springs in a motionless elevator. the springs all have the same spring constant given above. what is the magnitude of the force the bottom spring exerts on the lower mass? rank the distances the springs are extended from their unstretched lengths:

Well think of it like this, If we evolved from monkeys then why are there still monkeys around? Wouldn't every monkey be a human if "we evolved from monkeys" was true?This leads to the conclusion that both monkeys and humans evolved from a common ancestor rather than from each other.