This is a symbolic version of 41. A river has a steady

Chapter 3, Problem 3.3.42

(choose chapter or problem)

This is a symbolic version of 41. A river has a steady speed of vs. A student swims upstream a distance d and back to the starting point. (a) If the student can swim at a speed of v in still water, how much time tup does it take the student to swim upstream a distance d? Express the answer in terms of d, v, and vs. (b) Using the same variables, how much time tdown does it take to swim back downstream to the starting point? (c) Sum the answers found in parts (a) and (b) and show that the time ta required for the whole trip can be written as ta 5 2d/v 1 2 vs 2/v2 (d) How much time tb does the trip take in still water? (e) Which is larger, ta or tb? Is it always larger?