A 0.14 KG that is only in contact with a baseball for a very short 0.04 seconds. if the ball is accelerated from rest to 21 m/s, how much swinging force is required?

Could someone me find the answer to this problem.

The coefficient of friction is a number that represents the resistance to sliding between two in contact with one another.

What changes occur in the brain during the teenage years? 25 points, someone me out!a.) thinking becomes slower as the brain grows larger. b.) connections between neurons become stronger and faster. c.) unused neurons fuse together to form larger, better functioning neurons. d.) more neurons are developed.