A clown, mounted on stilts, loses his balance and falls backward from the position, where it is assumed the  = 0 when  = 07deg;. Paralyzed with fear,

A clown, mounted on stilts, loses his balance and falls backward from the position, where it is assumed the  = 0 when  = 07deg;. Paralyzed with fear, he remains rigid as he falls. His mass including the stilts is 80 kg, the mass center is at G, and the radius of gyration about G is k_G = 1.2 m. Determine the coefficient of friction between his shoes and the ground at A if it is observed that slipping occurs when  = 30°.