Answer
$1.61m/s^2$
Work Step by Step
We can find the required acceleration as follows:
$\Sigma F_y=N-mgcos\theta=0$
$\implies N=mgcos\theta$
Similarly $\Sigma F_x=mgsin\theta-f_k=ma$
$\implies ma=mgsin\theta-\mu_k N$
$\implies ma=mgins\theta-\mu_k(mgcos\theta)$
This simplifies to:
$a=g(sin\theta-\mu_Kcos\theta)$
We plug in the known values to obtain:
$a=(9.81)(sin26.5^{\circ}-(0.315)cos26.5^{\circ})$
$a=1.61m/s^2$