Solving the Problem of a Block Sliding Up an Inclined Plane

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Homework Help Overview

The discussion revolves around a physics problem involving a block sliding up a frictionless inclined plane, specifically analyzing the forces acting on the block and the resulting acceleration. The subject area is kinematics and dynamics, focusing on the effects of gravity on motion along an incline.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants explore the reasoning behind the negative sign in the force equations related to gravity on the incline. Questions are raised about the definitions of positive and negative directions in the context of the block's motion and the forces acting on it.

Discussion Status

Participants have engaged in a productive exchange, with some clarifying their understanding of the problem's setup and the implications of defining directions for velocity and acceleration. There is acknowledgment of the reasoning provided by others, indicating a collaborative exploration of the concepts involved.

Contextual Notes

One participant mentions their course, Engineering Physics I, which may imply a level of complexity in the problem that is appropriate for that academic context. Additionally, the discussion includes informal interactions among participants, suggesting a community atmosphere.

webren
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I have a question about this problem:

"A block is given an initial velocity of 5.00 m/s up a frictionless 20.0(degrees) incline. How far up the incline does the block slide before coming to a rest?"

The book gives a clue stating that mgx = -mgsin20.0 and mgy=-mgcos20.

My question is why is mgx negative mgsin20?

When I work it out:

Sum of x force = mgsin20 = ma,
therefore: a = gsin20

Do they make it negative because the force of gravity in the x direction is going in a negative direction while the velocity is going in a positive direction?
 
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I think it's negative becouse they defined the the direction of the initial velocity as positive, and so becous it's slowing down (along both the x and the y axis) the accelaration and force have to be negative.
 
What course are you taking? I'll be in the Clark building tomorrow. Taking my final exam

:smile: Whats your major?

Ans. Because gravity slows the block down as it slides up the incline.

The correct spelling is "because" lenin. Nice name BTW, clever.
 
Thank you.
 
:smile: I just noticed your red text, how appropriate,...commie.
 
Ah, both of your answers make sense. Thank you.

The class I am taking is Engineering Physics I.
I am a computer science major.

Looks like cyrusabdollahi and I go to the same school. Nifty.
 

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