- #1
j_confused
- 6
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Woo. Nevermind the rest of this message. I figured it out =))))
Hello all :)
Am having brain fart, I need help (obiviously) from the experts! All the tutorials and examples about the classic boat crossing a river aren't helping me with this problem.
"A woman can row a boat at 6.3 km/h in still water. (Assume i points to the far side of the river, perpendicular to the current, and j points in the direction of the current.)"
At this point, I drew a diagram. As for vectors, i is 105 m/min [answers require meters/minutes] perpendicular to shore, I assumed current to be heading east (downriver in my drawing).
___________________________________
...^...105 m/min i......|
...| .........5500m
...|.........|
...--------> 0 m/min j......|
This makes sense, b/c it would take roughly 52 mins to cross to a point directly across. Then comes the confusing bits...
(a) If she is crossing a river where the current is 3.2 km/h, in what direction must her boat be headed if she wants to reach a point directly opposite her starting point? (in degrees)
(b) How long will it take her to cross the river? (in minutes)
Based on the above, i is still 105 m/min and j is now ~53.3 m/min, so the resultant would be 117.5 m/min... I think.
From there, I'm lost. Please help!
-Jen
Hello all :)
Am having brain fart, I need help (obiviously) from the experts! All the tutorials and examples about the classic boat crossing a river aren't helping me with this problem.
"A woman can row a boat at 6.3 km/h in still water. (Assume i points to the far side of the river, perpendicular to the current, and j points in the direction of the current.)"
At this point, I drew a diagram. As for vectors, i is 105 m/min [answers require meters/minutes] perpendicular to shore, I assumed current to be heading east (downriver in my drawing).
___________________________________
...^...105 m/min i......|
...| .........5500m
...|.........|
...--------> 0 m/min j......|
This makes sense, b/c it would take roughly 52 mins to cross to a point directly across. Then comes the confusing bits...
(a) If she is crossing a river where the current is 3.2 km/h, in what direction must her boat be headed if she wants to reach a point directly opposite her starting point? (in degrees)
(b) How long will it take her to cross the river? (in minutes)
Based on the above, i is still 105 m/min and j is now ~53.3 m/min, so the resultant would be 117.5 m/min... I think.
From there, I'm lost. Please help!
-Jen
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