pysics

posted by .

A river is one mile wide and the water flows at the rate 3 miles/hour. If you can paddle a canoe 5 miles/hour in still water, then how long will it take you to paddle across the river and back? How long would it take you to travel one mile upstream (measured along the bank) and back?

  • pysics -

    To go straight across, you would have to paddle in an upstream direction with respect to the water. The velocity component across the river would then be sqrt(5^2 - 3^2) = 4 miles/h. The time to go across and back is then
    T1 = 2 mile/4 mph = 0.5 hours = 30 minutes

    To go 1 mile upstreeam and then down requires
    T2 = 1/(5-3) + 1/(5+3) = 1/2 + 1/8 = 5/8 hr = 37.5 minutes.

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. Math

    Alicia went on a steamboat ride up the Mississippi River. The boat travels 24 miles per hour in still water. How long will it take her to travel 54 miles upstream if the current of the river is 6 miles per hour?
  2. math

    A kayak moves 10 miles per hour in still water. If the river current flows at 5 miles per hour, how long does it take reach 26 miles upstream?
  3. Math

    Jared can paddle his canoe 1 mile upstream in 1 hour, but it takes only a half hour to paddle back the same distance. Find the speed of water. (Hint: d=rt and the rate or canoe speed, depending on which way he is going.)
  4. math

    Alicia went on a steamboat ride up the Mississippi River. The boat travels 20 miles per hour in still water. How long will it take her to travel 144 miles upstream if the current of the river is 8 miles per hour?
  5. Intermediate Algebra

    in still water, a paddle boat averages 10 miles per hour. It takes the boat the same amount of time to travel 36 mile downstream, with the current as 24 miles upstream, against the current. What is the rate of the water's current?
  6. Math

    Alicia went on a steamboat ride up the Mississippi River. The boat travels 20 miles per hour in still water. How long will it take her to travel 60 miles upstream if the current of the river is 8 miles per hour?
  7. Pre Calculus

    A motorboat travels 48 miles down a river in the same time it takes to travel 32 miles up the river. If the rate of the current is 4 miles per hour that is the rate of the boat still water?
  8. algebra

    joe is planning a 5 hour canoe trip. he can paddle 4 miles per hour in still water and the current is 3 miles per hour. how far downstream can he go?
  9. PHYSICS

    JOHN WANTS TO PADDLE HIS CANOE ACROSS A RIVER THAT IS 200M WIDE, HE STARTS FROM THE EAST SIDE. THE WATER CURRENT FLOWS NORTH-SOUTH AT 0.5MS^-1. IT TAKES JOHN 252S TO CROSS THE RIVER. 1. DRAW A DIAGRAM TO GRAPHICALLY REPRESENT THE VELOCTY …
  10. Algebra

    Petra, who can paddle her canoe at a rate of 12 mph in calm water, is paddling her canoe on a river whose current is 6 mph. How long will it take her to travel 3 miles upstream against the current?

More Similar Questions