Blocks A, B, and C have weights of 50 N. 25 N, and 15 N, respectively. Determine the small...

Blocks A, B, and C have weights of 50 N. 25 N, and 15 N, respectively. Determine the smallest horizontal force P that will cause impending motion. The coefficient of static friction between A and B is µs = 0.3, between B and C, µS = 0.4, and between block C and the ground, µS” = 0.35.