Question

An example of motion where speed is constant but velocity is variable

Answer 1

When a particle moves in a circular path then the velocity of particle changes continuously and this is tangential to the circular path.In a uniform circular motion the particle covers equal distance in equal time interval thus its speed (magnitude of velocity)  remains constant but as the motion is circular velocity always keep on changing in tangential direction.

 The velocity is changing so there is an tangential acceleration that is both velocity and acceleration changes in direction only.