Find the acceleration and tension in the string for the system above.

We start by drawing all the forces acting on each particle.

Resolving Perpendicular to the slope for P:

R-3g cos 30=0 rightarrow R=3g cos 30

Applying F=ma for P:

T-%mu R -3gsin 30 =3a

T-3 %mu gcos 30 -3gsin 30 =3a (1)

Applying F=ma for Q

2g-T=2a (2)

1. +(2)

Then from (2)