Solving F=MA: Boat Acceleration, Distance, Velocity

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Homework Help Overview

The discussion revolves around a physics problem involving a boat experiencing two forces: a forward push and a resistive friction force. The original poster seeks to determine the boat's acceleration, distance traveled over a specific time, final velocity, and weight, but notes a lack of information regarding the boat's mass.

Discussion Character

  • Exploratory, Assumption checking

Approaches and Questions Raised

  • Participants explore the implications of the provided forces and question whether the problem can be solved without knowing the mass of the boat. Some express skepticism about the problem's wording and its solvability with the given information.

Discussion Status

Several participants have pointed out the need for additional information, particularly the mass of the boat, to proceed with solving the problem. The original poster later confirms that the professor indicated the mass was omitted, suggesting a potential path forward once that information is clarified.

Contextual Notes

There is a noted concern regarding the realism of the problem, particularly about the assumption of a constant resistive force, which may not accurately reflect fluid dynamics.

smartjack
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Homework Statement


A boat moves through the water with two forces acting upon it. One is [F1x]=20000N forward push by the water on the propeller, and the other is [Ffrx]=2000n resistivive (friction) force due to the water around the bow
(A) What is the acceleration of the boat?
(B) If it starts from rest,how far will the boat move in 10s?
(C) what will the velocity be in the end of that time?
(D) what is the boat weight?


Homework Equations





The Attempt at a Solution

I know that the netforce will be 18000N but I really don't know where to go from there. I know the F=ma but without extra information I don't know what to do. Please help
 
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Is it even possible to solve with just this information?
 
smartjack said:

Homework Statement


A boat moves through the water with two forces acting upon it. One is [F1x]=20000N forward push by the water on the propeller, and the other is [Ffrx]=2000n resistivive (friction) force due to the water around the bow
(A) What is the acceleration of the boat?
(B) If it starts from rest,how far will the boat move in 10s?
(C) what will the velocity be in the end of that time?
(D) what is the boat weight?


Homework Equations





The Attempt at a Solution

I know that the netforce will be 18000N but I really don't know where to go from there. I know the F=ma but without extra information I don't know what to do. Please help
Where did you get this problem? Are you asked to solve in terms of the mass of the boat?

AM
 
I got this from my professor as part of my homework. No I am not asked to solve in terms of mass, it is exactly as I typed it.
 
smartjack said:
Is it even possible to solve with just this information?
Hi smartjack. http://img96.imageshack.us/img96/5725/red5e5etimes5e5e45e5e25.gif

You need additional information to solve this, e.g., the boat's mass.

Besides, it is an unrealistic situation, to say the boat experiences a constant friction force. Fluid friction varies steeply with speed.
 
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IF OP has given ALL information, this is indeed, stangely worded and insoluble. (That's why I highly doubt it is true)

IF, however, somewhere else, OP has been given a pseudoformula for the resistive force within which the mass of the boat is an included parameter, THEN the problem might be technically solvable.

(But, I would probably take issue with such a formula, but that's beside the main point here)
 
I talked to the professor, and he said he must have left out the mass of the boat. Which with the mass I can easily solve the problem. Thank you for your help, I tried to work on this for hours and was getting no where, I thought I had missed something fundamental in my classes.
 
smartjack said:
I talked to the professor, and he said he must have left out the mass of the boat. Which with the mass I can easily solve the problem. Thank you for your help, I tried to work on this for hours and was getting no where, I thought I had missed something fundamental in my classes.
Thanks for getting back. :smile:
 

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