2 boxes on flat ground and an incline

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Homework Help Overview

The discussion revolves around a physics problem involving two boxes, one on a flat surface and the other on an incline, with a focus on calculating acceleration and tension in a rope connecting them. The problem is set in the context of dynamics, specifically addressing forces acting on the boxes with and without friction.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning, Problem interpretation

Approaches and Questions Raised

  • Participants suggest starting with free body diagrams to identify forces acting on each box, including gravitational forces and their components along the incline. There are discussions about using trigonometry to resolve these forces and applying Newton's second law (F = ma). Some participants express uncertainty about how to begin and question the setup of the equations, particularly regarding the net force and its components.

Discussion Status

The discussion is active, with participants offering guidance on drawing free body diagrams and calculating forces. There is an acknowledgment of the complexity of the problem, particularly in resolving the equations involving tension and acceleration. Multiple interpretations of the forces and their relationships are being explored, but no consensus has been reached yet.

Contextual Notes

Participants are working under the constraints of a homework assignment, which may limit the information they can use or the methods they can apply. The presence of friction is also a variable under discussion, with different scenarios being considered.

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1. A 10 kg box on a level surface is attached by a weightless, unstretchable rope to a 7.0 kg box which rest on a 30 degree incline. Find the rate of acceleration and the tension in the rope if... a) there is no friction ... b) coefficient of friction is 0.10 for both boxes



2. F_net = m*a



3. Honestly, I'm not sure where to start
 
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Start with the box on the slope. Draw the force of gravity straight down and calculate its size in N. Draw a pair of vectors that begin and end in the same place as that first one, an arrow along the slope and another straight into the slope. Use trigonometry to figure out the size of each of these vectors. The force into the slope is canceled out (the slope pushes back equally), so it is the component along the slope that causes the two masses to accelerate. Use F = ma.
 
Do you know how to draw free body diagram? Identify the various forces acting on each body.
Find the net force acting in the downward direction. From that find the acceleration.

Edit: Hi Delphi51, we are racing.
 
Delphi51 said:
Start with the box on the slope. Draw the force of gravity straight down and calculate its size in N. Draw a pair of vectors that begin and end in the same place as that first one, an arrow along the slope and another straight into the slope. Use trigonometry to figure out the size of each of these vectors. The force into the slope is canceled out (the slope pushes back equally), so it is the component along the slope that causes the two masses to accelerate. Use F = ma.

rl.bhat said:
Do you know how to draw free body diagram? Identify the various forces acting on each body.
Find the net force acting in the downward direction. From that find the acceleration.

So is the F_net = F_gravity parallel - F_tension - F_friction? because that is what I got after drawing a free body diagram...

EDIT: and now I'm trying to solve and I'm getting an expression with two variables - tension and acceleration
 

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