Final answer:
The net force exerted on the block is the determinant of the block's acceleration, considering both the applied horizontal force and the frictional force. Since the fixed forces of gravity and normal force cancel each other out vertically, only horizontal forces will contribute to acceleration. The acceleration of the block will be to the right if the applied force is greater than the frictional force of 8 N; otherwise, it will be to the left.
Step-by-step explanation:
The given scenario involves forces, motion, and an understanding of Newton's laws of motion, specifically how a net force leads to acceleration in a frictionless environment. Since friction is present in this situation, it is the net force after accounting for friction that determines acceleration. The gravitational force acting on the block is 40 N, and the normal force exerted by the surface is also 40 N. These two forces are equal and opposite and therefore cancel out in the vertical direction, meaning there's no acceleration vertically.
Given the coefficient of friction (μ) is 0.20, we can calculate the frictional force as Ffriction = μ × N. Substituting the values, Ffriction = 0.20 × 40 N = 8 N. This frictional force opposes motion and therefore acts to the left if we assign the right direction as positive.
Since there's no other horizontal force mentioned, the net force Fnet is the applied force minus the frictional force. However, the applied force isn't given. Still, to find the block's acceleration, we use Newton's second law, Fnet = m × a . If Fnet points to the right, then the acceleration will be to the right, and if Fnet points to the left (meaning the frictional force is greater than the applied force), the acceleration will be to the left.