Work Done by Friction on 0.97 kg Ball Starting at h=9.9m

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Homework Help Overview

The problem involves a ball with a mass of 0.97 kg that starts at a height of 9.9 meters and slides down a smooth surface before encountering a rough surface, where it is brought to rest at a distance of 26.2 meters. The question focuses on determining the work done by friction in this scenario.

Discussion Character

  • Exploratory, Assumption checking, Conceptual clarification

Approaches and Questions Raised

  • Participants discuss the conservation of energy as the ball transitions from potential energy at height to kinetic energy and subsequently to work done against friction. Questions arise regarding the geometry of the problem, specifically whether the rough surface is horizontal.

Discussion Status

Some participants have provided hints related to potential energy and work done, encouraging the original poster to think critically about the relationships involved. There is an ongoing exploration of the concepts without a clear consensus or resolution yet.

Contextual Notes

There is a noted lack of complete information regarding the geometry of the problem, which may affect the analysis. Participants are also navigating the boundaries of providing guidance without giving direct solutions.

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Homework Statement


A ball starting at h= 9.9 meters slides down a smooth surface where it encounters a rough surface and is brought to rest at B a distance 26.2 meters away. If the ball has a mass of 0.97 kg, to the nearest joule, what is the work done by friction?

Any help to start this problem off?
 
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Iamaskier721 said:

Homework Statement


A ball starting at h= 9.9 meters slides down a smooth surface where it encounters a rough surface and is brought to rest at B a distance 26.2 meters away.

You have not given the complete geometry of the problem. Is the rough surface horizontal?

Anyway, the ball at the top had some property due to its height and that quantity is always conserved, and here it is dissipated totally by friction. That should be enough to answer the question.

As per your request, I'm just trying to start you off.
 
I wouldn't like to give you all the mathematical steps, but you should be able to solve this from whatever hint I am giving you.

When a mass is raised by a height h from some point, it gains some potential energy. When you let it fall back to its original level, this potential energy is converted into kinetic energy due to motion. Here, the ball stops because of friction. So where has all the kinetic energy gone? Has it got anything to do with the frictional force which opposes motion? Try to remember what is meant by "work done" .
 
You might have seen the following two equations in class, they might be a good starting point.

<< equations deleted by berkeman >>

For the original poster (OP) -- the equations that Banaticus wants you to think about relate

-1- the relationship between Potential Energy, the mass of an object, and the height to which it is lifted...

-2- the relationship between work done on an object, and the distance through which a force is applied...

Can you write out the two equations that Banaticus is referring to?

 
Last edited by a moderator:
Banaticus said:
You might have seen the following two equations in class, they might be a good starting point.

<< equations deleted by berkeman >>

For the original poster (OP) -- the equations that Banaticus wants you to think about relate

-1- the relationship between Potential Energy, the mass of an object, and the height to which it is lifted...

-2- the relationship between work done on an object, and the distance through which a force is applied...

Can you write out the two equations that Banaticus is referring to?


Sorry to have to edit your post, Banaticus. Giving the equations outright was a bit too much help. It takes a bit of practice to figure out how to help the OP to do the work themselves -- we definitely appreciate the help here!
 

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