In his rowboat, Pierre heads directly across a river at a speed of 10km/h. The river is flowing at km/h?

Question

In his rowboat, Pierre heads directly across a river at a speed of 10km/h. The river is flowing at km/h.
a) What is the resultant speed of the boat?
b)What angel will the resultant path of the boat make with the shoreline?
c)If the river is 120m wide, how far downstream will Pierre land on the opposite shore?

Answer 1

This is high school level mathematics. I hope this isn't homework. First of all the question is incomplete. You need to know the speed of the river. You only called it km/h.

Part c) is an important part of the question. With this information you know how long it should take to cross the river given the distance and km/h because distance = velocity x time. (note: you need to make sure you are in consitent units). Solve for time.

Now you know the time it takes to cross, so you should be easy to figure out the lateral distance travelled because distance = river velocity x time.

The last piece is the angle. Since you now know the distances and if you draw it will look like a right triangle. You will use a sine or cosine function to solve. Sine is defined as opposite over hypotenuse. So opposite to the angle you are calculating is the lateral distance travelled. Hypotenuse is the diagonal of the right triangle which can be calculated by Pythagorean's theorem. a^2 + b^2 = c^2 (where a,b are the sides of the right triange and c is the diagonal).

Answer 2

Make a comic strip. Resultant speed of boat = r = sq. root of (8^2 + 6^2) = 10 kph (Pythagoras) lower back utilizing Pythagoras, to go back and forth right now throughout the river,with the boat at 8 kph... Head the boat 40 8.6 ranges upstream, flow-river speed = 5.3 kph.

Answer 3

You need to know how fast the river is flowing.

Answer 4

What is the river current ?

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