Final answer:
The coefficient of friction for the surface must be 1 or greater.
Step-by-step explanation:
The fact that Devon is applying 100N of force to the object but it isn't moving indicates that the force of friction is greater than the applied force. The force of friction is determined by the coefficient of friction for the surface. In this case, the coefficient of friction must be greater than the ratio of the frictional force to the normal force, which is given by
μ = Ff / FN
where μ represents the coefficient of friction, Ff represents the force of friction, and FN represents the normal force. Since the object is not moving, the force of friction must be equal to the applied force, which means that the coefficient of friction is 1 or greater.