Swim Across Stream & Back
Calculate the time it takes swimmer #2 with speed s (wrt water) to go a distance w across stream and w back if the speed of the water is v (wrt bank).
- Note: this is more difficult because the swimmer must aim somewhat upstream of his final destination so that the current will carry him to the point directly across from the starting point.
- What is swimmer’s speed (wrt bank)?
- Pythagoras:
- vB2 = s2?- v2 ? vB = s sqrt (1 - (v/s) 2 )
- How long does it take the swimmer to cross the stream?
- Total Time:
T2 = 2T = ? (2w/s)
vB (smimmer wrt bank) = v (river wrt bank) + vs (swimmer wrt river)