If the horizontal force F = 20 lb is applied to block A, determine the accleration of block B. Neglect the firction if any.

1) 7.0 ft/s²
2) 7.3 ft/s²
3) 8.3 ft/s²
4) 9.5 ft/s²

From the free body diagram shown
For block A:
S F_x = ma_x and 20-N_B sin30^o = (8/32.2)a_A   ---------(1)

For block B:
S F_y = ma_y and N_B cos30^o - 10 = (10/32.2)a_B ------(2)
and s_B = s_Atan30^o and a_B = a_Atan30^o -----------------(3)
where s_A and s_B are distances travelled by blocks A and B in x and y directions respectively.

Solving equations (1)-(3) we have
a_A = 12.63 ft/s² and  N_B = 16.077 lb 
a_B = 7.29 ft/s²

So, the accleration of block B, a_B = 7.29 ft/s²