A solid sphere rolling up a slope is slowed down - is this only due to gravity, or is it also because of friction? 
I need to know this, to calculate the final translational and angular velocity of a solid sphere, at the top of the slope, initially rolling (pure roll) with velocity v on a plane surface and then comes onto this slope.. I'll do this using work - energy theorem, but I need to know the total work done on the sphere first.   

I think that friction is the only force that can affect the rotational motion of the sphere, as only it exerts a torque on the sphere..