(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Body A in Fig. 6-33 weighs 97 N, and body B weighs 91 N. The coefficients of friction between A and the incline are μs = 0.48 and μk = 0.25. Angle θ is 47°. Let the positive direction of an x axis be down the slope. What is the acceleration of A if A is initially (a) at rest, (b) moving up the incline, and (c) moving down the incline? Here is figure 6-33 http://edugen.wileyplus.com/edugen/cours… [Broken]

I have tried multiple attempts but they have been wrong. Obviously I know part a) is zero, but I need help with parts b) and C).

2. Relevant equations

F=ma

3. The attempt at a solution

I have tried multiple attempts but they have been wrong. Obviously I know part a) is zero, but I need help with parts b) and C).

Here is my attempt for B)

Fx: F(friction) + mg*sin(47) - F(B on A)=0 With some reworking and addition of numbers I got F(B on A)=71.1913 I set that equal to ma (F=ma) where mass is 97/9.8 and divided 71.1913 by (97/9.8) to get a=7.1925, after i found that that wasn't right, I didn't try for part c) but the 7.1925 would be negative because of how the axis are set up.

Now that I look at it I realize that F(friction) + mg*sin(47) - F(B on A) would not be equal to zero because it would be moving but I don't know where to go. Thanks!

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# Homework Help: Two objects on an incline with friction, calculate acceleration? B

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