6. (A12) A river is 400m wide, and the water in it flows from the west towards the east at a speed of 4m/s. Sarah is on the south side of the river and can row her boat at a speed of 5m/s through
the water.
a. If Sarah points her boats directly across the river, what is her resultant velocity with
respect to the shore (include both the magnitude and direction)? You must include a
diagram with your answer.
b. How far to the east does she has she travelled from her starting position when she
reaches the north shore?
C.
If she wants to have her boat to land directly north of where she started, what direction
should she point her boat?
d. If she points her boat in the direction you found in (c), how long will it take Sarah to get
across the river? (the equation d = v. t may be helpful)