Incline with friction and two blocks

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Homework Help Overview

The discussion revolves around a physics problem involving two blocks, one on an incline and the other hanging, with a focus on the effects of kinetic friction. Participants are tasked with finding the acceleration of the block and the tension in the string, given specific parameters such as mass and gravitational acceleration.

Discussion Character

  • Mixed

Approaches and Questions Raised

  • Participants express uncertainty about their calculations and assumptions regarding the direction of acceleration and forces acting on the blocks. There are attempts to clarify the signs of forces and the implications of the blocks' movements.

Discussion Status

The discussion includes multiple interpretations of the problem setup, with some participants questioning their assumptions about the direction of motion and the forces involved. Guidance has been offered regarding the sign conventions for forces, but no consensus has been reached on the correct approach or solution.

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. There is a noted assumption about the direction of acceleration for the blocks, which is being debated.

SakuRERE
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Homework Statement



The coefficient of kinetic friction between the block of mass m1 = 2.5 kg and the plane in Fig. 6 below is 1/6. Find (a) the acceleration of the block and (b) the tension in the string. Take g = 10 m/s2.
upload_2018-10-15_2-3-47.png


Homework Equations


Fnet=ma

The Attempt at a Solution


please i don't know what is the mistake here. the answer should be: a=2m/s^2 .
by the way i am assuming that the orange block is accelerating to the left down across the incline and so the green block up
this is my attempt :
upload_2018-10-15_2-5-11.png
 

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SakuRERE said:

Homework Statement



The coefficient of kinetic friction between the block of mass m1 = 2.5 kg and the plane in Fig. 6 below is 1/6. Find (a) the acceleration of the block and (b) the tension in the string. Take g = 10 m/s2.
View attachment 232186

Homework Equations


Fnet=ma

The Attempt at a Solution


please i don't know what is the mistake here. the answer should be: a=2m/s^2 .
by the way i am assuming that the orange block is accelerating to the left down across the incline and so the green block up
this is my attempt :
View attachment 232187
i got a=-3.7 m/s^2
 
I would change the sign of the tension force and the weight (mgsin(theta)) of block 1. Usually "up" the ramp is defined as positive.
 
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osilmag said:
I would change the sign of the tension force and the weight (mgsin(theta)) of block 1. Usually "up" the ramp is defined as positive.
do you mean that the system will move up right? like hanging block would go down
 
SakuRERE said:
do you mean that the system will move up right? like hanging block would go down

Compare the force of gravity on block 2 to that on block 1 when block 1 is on the ramp. Block 2 should go down.
 
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osilmag said:
Compare the force of gravity on block 2 to that on block 1 when block 1 is on the ramp. Block 2 should go down.
Thanks i got it just few seconds before you reply :smile:
 
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