Kinetic friction and acceleration

AI Thread Summary
The discussion revolves around calculating the acceleration of a 1.2 kg block on a table with a kinetic friction coefficient of 0.38. The user initially sets up free body diagrams and equations but struggles with the algebra involved in combining them. After some back-and-forth, they realize an error in their calculations and receive encouragement from another participant. Ultimately, the user corrects their approach and is guided to solve for acceleration. The conversation highlights the importance of careful algebraic manipulation in physics problems.
pumpernickel
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Hello everyone, I would appreciate some help with this problem:

The coefficient of kinetic friction between the 1.2 kg block in the figure below and the table is 0.38. What is the acceleration of the 1.2 kg block?

Homework Equations



F=M*A
Fk = μk * N

The Attempt at a Solution



I created freebody diagrams and came up with these

Block A: +T1 - WAE = Ma * a
Block B: + T2 - T1 - fk = Mb * a
Block C: + WCE - T2 = Mc * a

So I combined equations and came up with

WCE - WAE - fk = (Ma * a)+(Mb * a)+(Mc * a)

and fk= μk * N

and I thought it would be .38*1.2*9.8

but I know I am doing something wrong I just don't know what
 

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Looks ok to me...o wait I didn't check your combined equation..stand by...

Yes, looks good! Solve for a .
 
Last edited:
Alright, I redid my algebra and that is where the problem was...I am rather embarrassed! Thank you for your help PhanthomJay.
 
Great, good work, welcome to PF! :approve:
 

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