Solving Two Physics Questions for Kelly

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Discussion Overview

The discussion revolves around two physics problems posed by a participant named Kelly, focusing on concepts of forces, energy, and motion in different contexts. The first problem involves a mass dropped onto a snow-covered field and seeks to determine the average force exerted by the snow on the mass. The second problem concerns the movement of parallel hoses on the ground influenced by friction coefficients.

Discussion Character

  • Homework-related
  • Exploratory
  • Technical explanation

Main Points Raised

  • Kelly asks about the average force exerted by snow on a mass dropped from a height and how to approach the problem.
  • Another participant suggests calculating the kinetic energy of the mass upon reaching the snow and the work done by the snow to stop the mass.
  • Kelly questions what is actually stopping the mass, considering friction and the interaction with the snow.
  • A participant advises that the problem can be approached using kinematics and Newton's laws, suggesting that the potential gravitational energy must be equal to the work done by the snow.
  • There is a suggestion that the force exerted by the snow may come from compressing the snow and friction, but the exact mechanism is not fully explored.

Areas of Agreement / Disagreement

Participants express uncertainty about the exact nature of the forces involved in stopping the mass and whether friction plays a significant role. The discussion remains unresolved regarding the specifics of the forces and how they should be calculated.

Contextual Notes

There are limitations in the assumptions made about the forces acting on the mass and the interaction with the snow, as well as the need for clarity on the definitions of terms like "average force" and "work." The discussion does not resolve these ambiguities.

kelly.yasmin
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I have two questions and i have no clue how to solve them so please...

1. dropping a mass of M from some height H over a feid which is being covered with
a lot of snow. exentually the mass is in halt underneath the snow in deep D
the question is what is the average force that the snow is doing over the the mass during the process

2. two parallel hoses are sitting on the ground. there is a third one which is equal to those two and is putting above them.
the cofficient between the ground and the hoses is u1 and between hose 3 to the others
is u2. the question is wether the hoses will move and how

thank you very much. I am so lost...
Kelly
 
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kelly.yasmin said:
I have two questions and i have no clue how to solve them so please...

1. dropping a mass of M from some height H over a feid which is being covered with
a lot of snow. exentually the mass is in halt underneath the snow in deep D
the question is what is the average force that the snow is doing over the the mass during the process

2. two parallel hoses are sitting on the ground. there is a third one which is equal to those two and is putting above them.
the cofficient between the ground and the hoses is u1 and between hose 3 to the others
is u2. the question is wether the hoses will move and how

thank you very much. I am so lost...
Kelly

In the first problem, how much kinetic energy does the mass have when it reaches the snow? How much work, units of energy, must the snow do to stop the mass?
 
hey thanks for answering me.
I think i understand what you mean but therefore i would like to
ask is what is actually stopping the mass?
is it the friction (which i think that is countless here)
or is it something else? i was thinking maybe it can be the getting into the snow..
and still do i need calculate the time of all the process to get to the average force?
i really apreciate your help!
thank u very much
 
kelly.yasmin said:
hey thanks for answering me.
I think i understand what you mean but therefore i would like to
ask is what is actually stopping the mass?
is it the friction (which i think that is countless here)
or is it something else? i was thinking maybe it can be the getting into the snow..
and still do i need calculate the time of all the process to get to the average force?
i really apreciate your help!
thank u very much

Wait: have you learned work and energy yet? If not, you will have no idea about what I'm advising you to do.

Yes, you can solve this problem using kinematics by assuming a constant acceleration of gravity until it reaches the snow and a constant acceleration from snow until it stops. Then, you can relate the acceleration of snow solved for to the force causing it through Newton's first law.

Quicker, however, would be to say that all of the potential gravitational energy from being at a heigh H must be done by the snow by applying a constant force F over a distance D.

About your question, you don't need to become too attached to understanding how the snow is applying the force doing all of this - just assume it's a constant force and solve for it. The force probably comes mostly from compressing the snow and partly from friction.
 

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