Final answer:
The magnitude of the normal force on a box pulled along a frictionless surface is equal to the weight of the box, given that no other forces are acting on the box in the vertical direction.
Step-by-step explanation:
When you pull a box with a rope along a frictionless surface, the magnitude of the normal force on the box is equal to the weight of the box. Since the surface is frictionless, there is no frictional force to oppose the motion, and only the normal force and the weight act on the box perpendicularly.
Using the equation w = mg, where w is the weight, m is the mass, and g is the acceleration due to gravity (9.80 m/s²), we can determine that the normal force is equal in magnitude to the weight and directed perpendicular to the surface. For example, if a box has a mass of 100 kg, the normal force and the weight would both be 980 N (calculated as 100 kg × 9.80 m/s²).