Relative Velocity Boat Problem

In summary, to reach the boathouse 14 m downstream in 2.0 minutes with a current of 0.50 m/s in an 82 m wide river, one must row upstream at a speed of 0.38333 m/s and across the water at a speed of 0.68333 m/s. The resultant vector can be found using the Pythagorean theorem and the direction can be determined using trigonometry. The equation used is VBE = VBW + VWE, where VBE is the boat's velocity, VBW is the velocity of the boat in still water, and VWE is the velocity of the water.
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Homework Statement



You wish to paddle a boat across an 82 m wide river and land at a boathouse that is 14 m downstream of your starting point. If the current in the river is uniform at 0.50 m/s, how fast and in what direction do you need to row to reach the boathouse in 2.0 minutes?

Homework Equations


Relative Velocity equation
VBE = VBW + VWE

The Attempt at a Solution


[/B]
I know that in 2 minutes I would end up 60 m downstream.
(120 s)(0.50 m/s) = 60 m

This is 60 - 14 = 46 m away from the boathouse

Which means that I would need to row upstream at
46 m / 120 s = .38333 m/s
And row across the water at a speed of
82 m / 120 s = .68333 m/s
to be able to reach my destination in 2 min.

From this I'm assuming that I can use Pythagorean equation to solve for the resultant vector.
sqrt[(46m/120s)2 + (82m/120s)2] = .78351061 m/s

And then the angle of direction through trig
theta = arctan( (82m/120s) / (46m/120s) ) = 60.7 degrees upstream and across

I'm not sure if this is right because from the equation I get that
VWE = 0.50 m/s
 
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  • #2
I think your answer is correct. But I don't understand your last line :
"I'm not sure if this is right because from the equation I get that
VWE = 0.50 m/s"

And in your relative velocity equation , I don't get what does that "W" represent.
 

What is the "Relative Velocity Boat Problem"?

The relative velocity boat problem is a classic physics problem that involves calculating the speed and direction of a boat traveling in relation to a moving body of water. It is often used to demonstrate the concept of relative velocity and how it affects the motion of objects.

How do you solve the "Relative Velocity Boat Problem"?

To solve the relative velocity boat problem, you first need to identify the velocities and directions of the boat and the water. Then, you can use vector addition or the Pythagorean theorem to calculate the final velocity and direction of the boat.

What is the role of the wind in the "Relative Velocity Boat Problem"?

In the relative velocity boat problem, the wind is often used as a third vector to add to the velocity of the boat and the water. This allows for a more realistic scenario and demonstrates how multiple velocities can affect the motion of an object.

What are some real-life applications of the "Relative Velocity Boat Problem"?

The relative velocity boat problem has many real-life applications, such as calculating the speed and direction of boats or ships traveling in a river or ocean with a current. It is also used in navigation and aviation to determine the effects of wind on the motion of airplanes and ships.

What are some common misconceptions about the "Relative Velocity Boat Problem"?

One common misconception about the relative velocity boat problem is that the velocity of the boat is always equal to the velocity of the water. In reality, the boat's velocity is affected by the water's velocity, but it is not always equal. Another misconception is that the wind always blows in the same direction as the water, which is not always the case.

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