Cross a River: Time Needed for 1.5km Distance at 6.6km/h Speed

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To determine the time needed for a hunter to cross a 1.5 km wide river flowing at 6.6 km/h using a powerboat that moves at 14 km/h, one must first calculate the net velocity of the boat. This involves finding the angle of travel relative to the boat's speed vector, using the formula θ = tan⁻¹(v_river/v_boat). After establishing the angle, the effective distance across the river can be calculated, followed by determining the time required based on the net velocity. It is crucial to convert all units appropriately for accurate calculations. Understanding the vector components and drawing a diagram can aid in visualizing the problem.
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Homework Statement



A hunter wishes to cross a river that is 1.5 km
wide and that flows with a speed of 6.6 km/h.
The hunter uses a small powerboat that moves
at a maximum speed of 14 km/h with respect
to the water.
What is the time necessary for crossing if
the boat goes directly across the river? An-
swer in units of min.

Homework Equations


?


The Attempt at a Solution


I don't even know where to start.
 
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welcome to PF megamax48 :smile:

you need to find the net velocity acting on the boat, calculate the angle with respect to the boat speed vector [theta=tan[SUP]-1[/SUP] vy/vx=tan-1 vriver/vboat], get the distance using the angle and the river’s width, finally calculate the time using the calculated distance and the net velocity. you better draw this so you can understand it well

ps. don't forget to convert the units
 
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