Final answer:
The coefficient of friction in this scenario is 0. The incline angle at which the block will slide at a constant velocity is equal to the angle of the block's weight vector.
Step-by-step explanation:
To determine the coefficient of friction in this scenario, we need to use the formula:
frictional force = coefficient of friction * normal force
Since the surface is frictionless, the frictional force is 0. Therefore, the coefficient of friction is also 0.
In order for the block to slide down the inclined surface at a constant velocity, the force of gravity acting down the slope needs to be balanced by the component of the force of gravity perpendicular to the slope. This can be achieved when the incline angle is equal to the angle of the block's weight vector.