Final answer:
The net force perpendicular to the slope is zero because there is no acceleration in that direction. The normal force is equal in magnitude to the component of weight perpendicular to the slope, balancing out the forces.
Step-by-step explanation:
The net force in the direction perpendicular to the slope is zero. This is because there is no acceleration in this direction, therefore the forces perpendicular to the slope add up to zero. The skier's weight has a component parallel to the slope (Wx) and a component perpendicular to the slope (Wy). Since there is no motion perpendicular to the slope, the normal force (N) is equal in magnitude to Wy, balancing out the component of weight.