Question

A sled of mass m = 70.0 kg is being pulled horizontally on a frictionless floor by a force F = 420 N that makes an angle 20.0o above the horizontal. What is the magnitude of the normal force applied by the ground on the sled?
Henry
M*g = 70 * 9.8 = 686 N. = Wt. of sled.

Fn = Mg-F*sin20 =