The forces acting on the block on the incline will be its weight (straight down, of course), the normal force (normal, i.e. perpendicular, to the plane, and counteracting that component of the weight also normal to the incline) and the tension in the rope. You’ll need to decompose the weight into components parallel to and perpendicular to the plane. The perpendicular component will be cancelled by the normal force. The parallel component will be what actually pulls the whole system.

Now here’s the key: you have two models for friction. One is the static model, with its own coefficient, and the other is the kinetic model. The static model applies if the system isn’t moving, the kinetic model applies if it is. You’ve only been given the kinetic coefficient (which, by the way, is typically less than the static coefficient), which implies that the system will be moving. This is good, because the kinetic model is very simple. Kinetic friction is always the coefficient of friction times the normal force, no matter how fast things are moving. So, figure out the kinetic friction, figure out the force pulling the block on the incline down the plane (the mass of the block on the plane times the component of gravity pulling it parallel to the plane) and subtract them, and you’ll have your net force on the system. You can get the acceleration, then, by taking that net force and dividing by the total mass of the system, i.e. m1 + m2.

As a general rule, always start these problems with a free body diagram.

For 4 kg mass it will be 0.5 x 4 = 2 kgs

For 2 kg mass it will be 0.5 x 2 = 1 kg.

For an inclined plane the acceleration = g x sin (theta)

Where theta is the angle made by the plane with the horizontal.

This is independent of the mass. In this case friction is also given as absent.