1. Why do bicycle riders lean inward when rounding a curve at high speed?
2. A girl is whirling a ball on a string around her head in a horizontal plane. She wants to let go at precisely the right time so that the ball will hit a target on the other side of the yard. When should she let go of the string?
3. Points A, B, and C have coordinates (3,2,1), (5,4,2), and (−4, 2, 1) respectively.
Find the scalar product of A−!B and A−!C.