Question

A person in a canoe wants to cross a 65-foot river. He begins to paddle straight across the river at 1.2 m/s while a current is flowing perpendicular to the canoe. If the resulting velocity of the canoe is 3.2 m/s, what is the speed of the current to the nearest tenth?

Answer 1

2.97 m/s

Answer 2

@srinuscooby Mind telling me how you worked it?

Answer 3

OOpz, am sorry. I didn't notice. Okay here you go. I'm telling you how :)

Answer 4

here the give values are :
Resultant velocity : R=3.2m/s
paddling speed, lets say a=1.2m/s
speed of current, lets say b is unknown and we need to find :)
Now as mentioned "current is flowing perpendicular to the canoe" which means theta=90
Hence, in equation:
\[R=\sqrt{{a ^{2}}+b ^{2}+2abcos \theta}\]

We know that cos90=0
hence remaining expression would be as :
\[R=\sqrt{a ^{2}+b ^{2}}\]

Simply that and you wil get 2.966479394838265 m/s.
Then you would be done :)