A swimmer can propel herself through still water at a constant speed of relative to…
PHYSICS · Multi-part · A Level · Physics · Mechanics and materials · Mechanics and materials
Problem
A swimmer can propel herself through still water at a constant speed of 1.5ms−1 relative to the water. She wishes to cross a river that is 120m wide; the current flows due west at 0.80ms−1. Treat due north as the +y axis and due east as the +x axis.
(a) Let the swimmer aim so that she lands directly across from her starting point on the opposite bank. Determine the required heading, expressed as an angle measured east of north.
(b) Using this heading, find the swimmer’s resulting velocity components relative to the ground.
(c) Calculate the time it takes her to reach the opposite bank.
(d) Suppose instead she aims straight toward the opposite bank (due north). Determine how far downstream (west) she will land under that strategy.