A boat crosses a river of width w=100 m in which the current has a uniform speed of 1.35 m/s. The pilot maintains a bearing perpendicular to the river

asked 2021-02-14
A boat crosses a river of width w=100 m in which the current has a uniform speed of 1.35 m/s. The pilot maintains a bearing perpendicular to the river and a throttle setting to give a constant speed of 2.00m/s relative to the water. What is the speed of the boat relative to a stationary observer on the shore?

Answers (1)


speed of the boat relative to water=2m/sec
speed of water=1.35m/sec
angle between these two = 90degree.
so the speed of the boat relative to stationaryobserver \(\displaystyle=\sqrt{{{2}\cdot{2}+{1.35}\cdot{1.35}}}={2.412}\frac{{m}}{{\sec{}}}\)
the angle made with the direction offlow \(\displaystyle= \tan{\theta}=\frac{2}{{1.35}}\Rightarrow\theta={55.98}\ \text{ degree }\)​​​​​​​

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