Dynamics: Incline Slope Derivation Simplification

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Homework Help Overview

The discussion revolves around a dynamics problem involving a block on an incline with an applied force acting at an angle. The original poster describes a study guide exercise that requires simplification of equations related to forces acting on the block, including gravitational and applied forces.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • The original poster attempts to substitute equations to simplify the expression for net force and is seeking advice on how to proceed with the simplification. Some participants question the clarity of the force arrangement and whether the applied force is acting horizontally or at an angle. Others suggest using trigonometric identities to express forces in terms of tangent.

Discussion Status

The discussion is ongoing, with participants exploring different interpretations of the force arrangement and seeking clarification on the applied force's direction. There is a focus on understanding the relationships between the forces involved, but no consensus has been reached regarding the setup.

Contextual Notes

There is mention of missing values and the nature of the problem being a fill-in-the-blank study guide, which may limit the information available for discussion. The original poster expresses difficulty with simplification, indicating a potential gap in understanding the underlying concepts.

Asleky
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Homework Statement


No official problem, just a study guide fill-in-the-blanks with an extended simplification blank. Basically, no values were given, and it is a standard block on a standard slope with a north-east applied force pushing down on the block (not parallel to horizontal or vertical axis).

Homework Equations


Fnet = ma
Fnormal = Fay + Fgy
Fnormal = (Fapplied)(sinØ) + (Fgravity)(cosØ)
Fnet = Fax - Fgx - Ffk
Fnet = (Fapplied)(cosØ) - (Fgravity)(sinØ) - (Uk)(Fnormal)

The Attempt at a Solution


He asked us to substitute the second equation above into the third equation above. I am terrible at simplifying and so this is as far as I've gotten:
ma = (Fapplied)(cosØ) - (Fgravity)(sinØ) -Uk(Fapplied)(sinØ) + (Fgravity)(cosØ)
This is extremely messy and confusing, I am aware, so I am in deep gratitude to anyone taking time to help a scrub physics student like me. :D Thank you so much for any simplifying advice! I am solving for acceleration.
 
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Actually upon further inspection, could I somehow make it (Fapplied)(tanØ) and (Fgravity)(tanØ)? I am confident that the trig law tanØ = sinØ/cosØ will be used. At least I'm on to something :(
 
The arrangement is not clear. Are you saying that the force is acting down the slope and parallel to it?
According to this equation
Asleky said:
Fnormal = (Fapplied)(sinØ) + (Fgravity)(cosØ)
the applied force is horizontal.
 
haruspex said:
The arrangement is not clear. Are you saying that the force is acting down the slope and parallel to it?
According to this equation
the applied force is horizontal.
Yeah that's why I multiplied by sin and cos to make all the components on one axis.
 
haruspex said:
According to this equation ... the applied force is horizontal.
Asleky said:
Yeah that's why I multiplied by sin and cos to make all the components on one axis.
But you wrote in the OP:
Asleky said:
with a north-east applied force pushing down on the block (not parallel to horizontal or vertical axis)
So which is it? Is the applied force horizontal or at an angle?
 
Could you draw a FBD?
 

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