Answer:
1/2
Step-by-step explanation:
We need to make a couple of considerations but basically the problem is solved through the conservation of energy.
I attached a diagram for the two surfaces and begin to make the necessary considerations.
Rough Surface,
We know that force is equal to,



Matching the two equation we have,


Applying energy conservation,





Frictionless surface




Given the description we apply energy conservation taking into account the inertia of a sphere. Then the relation between
and
is given by

