# How Far is the Boat From its Original Position?

• Benjamin_harsh
In summary, a boat goes upstream for 3 hours and 30 minutes and then goes downstream for 2 hours and 30 minutes. The speed of the current is 10/3 kmph and the speed of the boat in still water is 15/2 kmph. To find out how far the boat is from its original position, we need to solve the problem using references, as the boat's speed and direction are relative to the water and the land. Another approach is to determine the boat's speed relative to land on the upstream and downstream portions of the trip.
Benjamin_harsh
Homework Statement
How far from its original position is the boat now?
Relevant Equations
With reference to ground, the water travels downstream for 2.5+3.5= 6 hours.
With reference to water, the boat went upstream for 1 hour. So the boat is

10/3×6−15/2×1=12.5 km downstream from the start.
A boat goes upstream for 3 hr 30 min and then goes downstream for 2 hr 30 min. If the speed of the current and the speed of the boat in still water are 10/3 kmph and 15/2 kmph respectively, how far from its original position is the boat now?

With reference to ground, the water travels downstream for 2.5+3.5= 6 hours.
With reference to water, the boat went upstream for 1 hour. So the boat is

Final Equation: 10/3×6−15/2×1=12.5 km downstream from the start.

Why should we solve this question through references?

How boat went upstream for 1 hour if question clearly says boat goes upstream for 3 hr 30 min?

Last edited by a moderator:
Benjamin_harsh said:
How boat went upstream for 1 hour if question clearly says boat goes upstream for 3 hr 30 min?
You seem to have stated the problem twice with different values. What is the actual statement of the problem, as stated wherever you got it from?

phinds said:
You seem to have stated the problem twice with different values. What is the actual statement of the problem, as stated wherever you got it from?

Why should we solve this question through references?

berkeman
Benjamin_harsh said:
Why should we solve this question through references?
Because the boat is moving through the water, which is itself moving. If the boat's speed was only 10/3 km/hr, and it was traveling upstream, it would stay in the same place, relative to the ground, but would have traveled 10/3 km in an hour, relative to the water.

Benjamin_harsh said:
Why should we solve this question through references?
What references are you referring to?
Frames of Reference?

Moving on, in an effort to see how you attempted to solve this problem:
The information in your original post appears to be rather scrambled. I did manage to pick out the actual problem.
A boat goes upstream for 3 hr 30 min and then goes downstream for 2 hr 30 min. If the speed of the current and the speed of the boat in still water are 10/3 kmph and 15/2 kmph respectively, how far from its original position is the boat now?​

Then fast forward to what you call the
Final Equation: 10/3×6−15/2×1=12.5 km downstream from the start.​
I agree that this is the correct answer numerically, but does this solution make sense?

Let's see. 10/3 (km/h) is the speed of the water. That's downstream and with respect to (w.r.t) dry land.
Also, 15/2 (km/h) is the speed of the boat in still water. I.e. The boat travels at a speed of 15/2 (km/h) w.r.t. the water.
Digging through the OP, we find your explanation of where the 6 and the 1 come from and that both are in units of hours.
With reference to ground, the water travels downstream for 2.5+3.5= 6 hours.​
With reference to water, the boat went upstream for 1 hour.​
(By the way: I notice that your solution does use references.)

Multiplying 10/3 km/h by 6 h makes sense and could possibly be useful in solving this problem.

But, what do you mean by "the boat went upstream for 1 hour"? You then multiply this by the speed of the boat w.r.t. the water, which you subtract from the distance the water moved in the entire 6 hours.
The boat goes upstream for 3.5, not just 1 hour, then goes downstream for another 2.5 hours.

You have the boat going upstream for just 1 hour, then what? What does it do the other 5 hours?

You haven't fully explained your reasoning here.
.

jim mcnamara
SammyS said:
With reference to ground, the water travels downstream for 2.5+3.5= 6 hours.
With reference to water, the boat went upstream for 1 hour.

How boat went upstream for 1 hour only if question clearly says boat goes upstream for 3 hr 30 min?

My doubt regarding the way of approach to answer.

Benjamin_harsh said:
How boat went upstream for 1 hour only if question clearly says boat goes upstream for 3 hr 30 min?

My doubt regarding the way of approach to answer.
"A boat goes upstream for 3 hr 30 min and then goes downstream for 2 hr 30 min". 3.5hr - 2.5hr = 1hr

Merlin3189
Benjamin_harsh said:
How boat went upstream for 1 hour only if question clearly says boat goes upstream for 3 hr 30 min?

My doubt regarding the way of approach to answer.
So, that solution to the problem in the Original Post is not your solution? I misunderstood that.

Was that solution given to you written out in the manner you posted ? It does seem to me that the approach is somewhat unusual.

SammyS said:
It does seem to me that the approach is somewhat unusual.

Can you show me another simple approach ?

Benjamin_harsh said:
Can you show me another simple approach ?
Yes, we can get you started on another approach. But first ...

Benjamin_harsh said:
Why should we solve this question through references?
It is absolutely necessary due to the information given in the problem itself. The two given speeds are in reference to different objects: the land for the water, the water for the boat. Right?

Now for an alternate approach:
What is the boat's speed relative to land on the upstream portion of the trip?
What is the boat's speed relative to land on the downstream portion of the trip?

## 1. Why is referencing the ground and water important in scientific research?

Referencing the ground and water is important in scientific research because they are two of the most vital components of our environment. The ground provides a habitat for many living organisms and plays a crucial role in nutrient cycling and water filtration. Water, on the other hand, is essential for all life forms and is a key factor in many processes such as photosynthesis and hydration. By referencing these elements, we can better understand the natural systems in which our research is conducted.

## 2. How does referencing the ground and water contribute to the accuracy of scientific studies?

Referencing the ground and water helps to ensure the accuracy of scientific studies by providing a baseline for comparison. By understanding the natural state of these elements in a given area, we can more accurately measure the impact of our research and determine if any changes are significant. Additionally, referencing the ground and water can help to eliminate confounding variables and provide a more precise understanding of cause and effect relationships in our studies.

## 3. Can referencing the ground and water help to identify potential environmental impacts?

Yes, referencing the ground and water can help to identify potential environmental impacts. By studying the natural state of the ground and water in a particular area, we can establish a baseline and compare it to future data. This can help us to identify any changes or disruptions that may be caused by human activities or natural events. By understanding these impacts, we can work towards mitigating them and promoting a healthier environment.

## 4. In what ways can referencing the ground and water improve the validity of scientific research?

Referencing the ground and water can improve the validity of scientific research in several ways. It can help to eliminate bias by providing a standard for comparison and ensuring that all data is collected and analyzed objectively. Additionally, referencing these elements can help to increase the reproducibility of studies by providing a clear understanding of the environmental conditions in which the research was conducted. This can also help to promote transparency and establish trust in the scientific community.

## 5. How can referencing the ground and water contribute to the conservation of natural resources?

Referencing the ground and water is crucial for the conservation of natural resources. By studying these elements, we can better understand their role in the ecosystem and their relationship with other living organisms. This knowledge can inform conservation efforts and help us to make more sustainable decisions. Additionally, referencing the ground and water can help us to identify and monitor changes in these resources, which can aid in the development of conservation strategies and the protection of our environment.

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