Cart, Incline, Pulley, and a messed up Acceleration.

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Homework Help Overview

The discussion revolves around a physics problem involving a cart on an incline connected to a pulley system. The original poster is attempting to calculate the acceleration of the system but is encountering a discrepancy between their result and the expected answer.

Discussion Character

  • Exploratory, Assumption checking, Mathematical reasoning

Approaches and Questions Raised

  • The original poster shares their calculation for acceleration and questions the source of their error. Participants suggest uploading the problem image for clarity and discuss the correct angle to use in calculations. There is also mention of the forces acting on the system, including gravitational components.

Discussion Status

Participants are actively engaging with the problem, offering suggestions for clarifying the setup and discussing the forces involved. Some have provided equations that could lead to a more accurate calculation of acceleration, indicating a productive exploration of the topic.

Contextual Notes

There is a noted confusion regarding the angle used in calculations, with participants emphasizing the importance of using the correct angle for the gravitational force component. The original poster's calculations are based on an angle of 26 degrees, while there was a mention of 64 degrees that needed clarification.

Some_Thing
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The question and my work can be seen in the image below:

http://img145.imageshack.us/img145/550/scan0001fgu.jpg

The problem is that I am getting around 1 for acceleration, while the answer is 0.77.

What am I doing wrong?
 
Last edited by a moderator:
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rock.freak667 said:
Upload the image here [URL]http://imageshack.us and paste the forum code so that we can see it and try to help you.

Oops, I was using a url from hotmail. It showed up fine for me, but I guess that was because I was logged in at the time.

Thanks.
 
Last edited by a moderator:
The angle remains 26 and not 64. So Fgx = mass x gravity x sin theta where theta is 26 degrees.
 
math_04 said:
The angle remains 26 and not 64. So Fgx = mass x gravity x sin theta where theta is 26 degrees.

Fgx = mass x gravity x sin 26

Fgx = 3.6 x 9.8 x sin 26

Fgx = 15.465

This rounds off to 15.5 N, which is what I got.


NOTE: cos 64 = sin 26
 
You have got another force in the rope m2a.
Your equation should look something like this:

m2g+m2a+m1a=m1gsin26

a=(m1gsin26-m2g)/(m1+m2)
a=0.7728
 

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