A 10 kg mass is at rest on a horizontal surface with no forces other than gravity and the normal force acting on it. (a) Given that the coefficients of static friction between the surface and the mass are 0.5 and 0.2, respectively: (I) what is the force of static friction between the object and the surface? (ii) what minimum horizontal force is required to start the object sliding? (b) If the force in (a)(ii) above continues to act on the object after it starts sliding, what will be the object's acceleration?