A wheel of radius R is rolling without slipping. The velocity of the point on the rim that is in contact with the surface, relative to the surface is:
a) equal to Rw in the direction of motion of the center of mass.
b) equal to Rw opposite the direction of motion of the center of mass.
c) Zero.
d) equal to the velocity of the center of mass and in the same direction
e) equal to the velocity of the center of mass but in the opposite direction.