Electromagnetic radiation transfers momentum to the surface it strikes. This implies that solar radiation can exert a small force on objects in the solar system. The force is given by F = 2IA / c, where I is the intensity of radiation, A is the area of the object, and c is the speed of light. The possibility of using this radiation pressure to propel spacecraft out of the solar system has been raised. Calculate the force on a 0.5 km square solar sail at the distance from Earth, where I = 1400 Watt/m^2.