Answer
(a) downward
(b) $0.92m/s^2$
Work Step by Step
(a) We know that
$a=(\frac{m-Msin\theta}{m+M})g$
We plug in the known values to obtain:
$a=(\frac{4.2-(5.7)sin35^{\circ}}{4.2+5.7})(9.81)$
$a=0.92m/s^2$
The positive sign shows that the direction of acceleration of the hanging block is downward.
(b) As from part(a), we can see that the magnitude of acceleration is $0.92m/s^2$.
