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CloudKel

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## Homework Statement

Relative velocity question. A power boat has cruising speed of 60 km/hr. It is

taking part in a race around three buoys arranged in an equilateral triangle. The

second buoy, B, is 5 km due East of the starting/finishing buoy, A. The third

buoy, C, is to the North of the line joining A and B. There is a current flowing at

10 km/hr from the south-west. In what direction should the boat be steered on

each leg of the race and how long will it take the boat to complete one circuit.

## Homework Equations

Vb = Vb/w + Vw

## The Attempt at a Solution

A to B

Vw = 5(square root 2)i + 5(square root 2)j

Vb/w 60Cos(theta)i + 60Sin(theta)j

Vb = 5(square root 2) + 60Cos(theta)i + 5(square root 2)+ 60Sin(theta)j

5(square root 2)+ 60Sin(theta)j = o

Sin(theta) =5(square root 2) / 60

theta = 6.77

5(square root 2) + 60Cos(6.77)i =66.65i

Vb = 66.65i + 0j

t = 0.075hrs

t = 270.068s