Friction: a 4

Multiple Choice

Friction: 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