Need help with this probelm not with the maths involved but the theory,

Wheel radius R rolls to the right along straight line with speed v, the path of a point on the rim is given by;

c(t)= ( vt - Rsin((vt)/R) , R-Rcos((vt)/R) )

When is the velocity vector of this point horizontal and what is the speed at this point?

Trying To work out when velocity is horizontal?