Two bicycles A and B are turning around a circle of radius R as shown from above. At t=0, they start from the same point 1 and follow the points 2, 3, 4 in counterclockwise sense. A moves at constant speed vA while B moves at constant speed vB (vB = 3/4 vA).
a- What is the velocity vector vA of bicycle A (in unit vector notation) when A passes by the starting point 1? (4 pts)
b- When A completes the first lap (arrives at point 1 again), what is the displacement ΔrB of bicycle B from t=0 (in unit vector notation)? (5 pts)
c- What is vBA, the relative velocity of bicycle B as measured by bicycle A when A passes by the starting point 1 again? (5 pts)