Calculating Acceleration of Blocks on a Ramp

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The discussion revolves around calculating the acceleration of blocks A and B on a ramp, with specific weights and coefficients of friction provided. Part (a) involves determining the minimum weight of block C to prevent block A from sliding, which was successfully calculated as 4.8 N. In part (b), the user struggles to find the correct acceleration of block A after block C is lifted, initially misapplying tension values and equations. The correct approach requires setting up separate equations for both blocks and ensuring that masses, not weights, are used in calculations. Ultimately, the user is reminded to correctly account for the masses to find the accurate acceleration.
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Homework Statement


In Fig. 6-35, blocks A and B have weights of 51 N and 23 N, respectively. (a) Determine the minimum weight of block C to keep A from sliding if μs between A and the table is 0.23. (b) Block C suddenly is lifted off A. What is the acceleration of block A if μk between A and the table is 0.12?
**image is attached**

Homework Equations


fxnet= T-fs=ma
fymet= FN-Wc-Wa=0

fxnet=T-UkFn=ma

The Attempt at a Solution



I completed part (a) and got 4.8 to be the answer, however, I didnt get part (b), I tried to use the tension I got from part (a) and put it in the 3rd equation above and got -14,472 which is obviously not correct. Can anyone tell me what I'm doing wrong?
 

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The tension is not the same once things start accelerating. You'll have to set up equations for both masses and solve for the acceleration (and new tension).
 
Okay, I did that... the second two equations were Fxnet= T-Uk(WA)=ma and Fynet= Wb-T=ma and when I added them together I got Wb - Uk(Wa)=(ma + mb)a and then solved for a and got 0.23 for the answer, and it was yet again wrong. What am I doing that's not right again?
 
Be sure when calculating ma + mb that you are adding the masses and not the weights.
 

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