= Solution
The inclined parcel has <tension> $T$ up the slope, weight $mg$ vertically downward, <normal reaction> $N=mg\cos\theta$ and <friction> $\mu mg\cos\theta$ down the slope. The hanging <mass> has weight downward and <tension> upward. The ideal string makes the two <acceleration> magnitudes equal.
The <velocity> slope is \b[$a=2.4/1.5=1.60\,\mathrm{m\,s^{-2}}$], up the track for the parcel and downward for the hanging <mass>. The <free-body diagrams> show gravity itself as one vector; its slope-parallel and normal components are used in the equations rather than counted as additional <forces>.
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