Question
A kayaker needs to paddle north across a 85 m wide harbor. The tide is going out, creating a tidal current that flows to the east at 1.6 m/s. The kayaker can paddle with a speed of 2.8 m/s.
(a) In which direction should he paddle in order to travel straight across the harbor?
(a) In which direction should he paddle in order to travel straight across the harbor?
Answers
skipper
85/2.8=30.36 secs. to travel straight across. in the time he would have end up (30.36 x 1.6) = 48.57 m. downstream so now you can sketch a right triangle, 85 m. north/south, south 48.57 m. "upstream" on the far bank.
(a) angle to row = 48.57/85 = 0.57 deg, west of north.
(b) distance he actually paddles = sqrt. (85^2 + 48.57^2), 98 meters
time 98/2.8 = 35 secs
(a) angle to row = 48.57/85 = 0.57 deg, west of north.
(b) distance he actually paddles = sqrt. (85^2 + 48.57^2), 98 meters
time 98/2.8 = 35 secs