The 10 lb block A and the 20 lb block B are initially at rest. If a force of P = 10 lb is applied to B as shown, determine the accleration of each block. The coefficient of kinetic friction between any two surfaces is mk = 0.2 and the coefficient of static friction is
ms = 0.3.Note that A slips on B.

1) 6.44 ft/s2 and 3.22 ft/s2
2) 5.5 ft/s2 and 4.23 ft/s2
3) 1.38 ft/s2 and 2.38 ft/s2
4) 6.25 ft/s2 and 3.28 ft/s2

Since A slips on B as B slips:
For block A: S Fx = max ( from the free body of A)
2 = (10/32.2)aA    and aA = 6.44 ft/s2

For block B: S Fx = max  (from the free body of B)
10 - 6 -2 = (20/32.2)aB and aB = 3.22 ft/s2

So the accleration of A, aA = 6.44 ft/s2
and the accleration of B, aA = 3.22 ft/s2