1. Discuss how it is possible that a flock of birds in flight can have a momentum of zero but not have zero kinetic energy. 2. Discuss the design of the roller coaster shown in the sketch in terms of...

1. Discuss how it is possible that a flock of birds in flight can have a momentum of zero but not have zero kinetic energy.

2. Discuss the design of the roller coaster shown in the sketch in terms of the conservation of energy

3. Consider the identical balls released from rest on tracks A and B as shown. When each ball has reached the right end of its track, which will have the greater speed?