For this exercise let's use Newton's second law, in this case our reference system has an axis parallel to the plane, we will call it the x-axis and we assume that the downward direction is positive, an y- axis perpendicular to the plane. Let's write Newton's second law for each axis
x axis
Wₓ = m a
y Axis
N - W_y =
N = W_y
let's use trigonometry to find the components of the weight
sin θ = Wₓ / W
Wx = W sin θ
cos θ = W_y / W
W_y = W cos θ
we substitute
Fₓ = mg sin θ = m a
Fₓ = 10 0.1
Fₓ = 1 N
This is the force that makes the box slide down and a component of the box's weight.
