A 400-Kg Block Rests Between the Floor and a 3

Multiple Choice

A 4.00-kg block rests between the floor and a 3.00-kg block as shown in the figure.The 3.00-kg block is tied to a wall by a horizontal rope.If the coefficient of static friction is 0.800 between each pair of surfaces in contact,what horizontal force F must be applied to the 4.00-kg block to make it move?

A) 16.2 N
B) 54.9 N
C) 21.1 N
D) 23.5 N
E) 78.4 N