In a perfectly elastic collision, a 0.400 kg ball moving toward the east at 3.7 m/s suddenly collides head-on with a 0.200 kg ball sitting at rest.

the answer is c i did the same question so i know that's right!

d. air pressure decreases as altitude increases.

the five characteristics of adolescence are biological growth and development, and undefined status, increased decision making, increased pressure and the search of self.