Hello!!!!

Hope you are doing great!!!

Yes , We can apply a=(gsinθ - μgcosθ)

Σ F = Fg - Fk  ( Fg is force exerted by the block , Fk is the frictional force,  we can consider frictional force according to the question)

Σ F=(mgsinθ - μmgcosθ),,θ is the angle of the inclined plane and by balancing the forces we get this equation

Σ F=  m(gsinθ - μgcosθ),,,as f=ma

ma=m(gsinθ - μgcosθ),

by cancelling m on both sides,we get,,

a=(gsinθ - μgcosθ)

As per  the equation of kinematics ;;

s=ut+1/2at^2,,as initial velocity will be zero,,

s=1/2at^2

t^2=2s/a

t^2=2s/(gsinθ - μgcosθ)

t= √  2s/(gsinθ - μgcosθ)

Hope it helps!!!