A sled of m m = 70 kg is being pulled horizontally on a frictionless floor by a force F = 480 N that makes?

A sled of m m = 70 kg is being pulled horizontally on a frictionless floor by a force F = 480 N that makes an angle 20o above the horizontal. What is the magnitude of the normal force applied by the ground on the sled? (g = 9.8 m/s2)