Give a suitable example of the condition when a body moves but speed is constant

Dear student,

A body can have a constant speed but a changing velocity because the direction can change while the speed is constant. 
For example, A body or a car in a uniform circular motion satisfies all your conditions. A body in uniform circular motion has a constant speed, but the velocity varies as the direction of the velocity changes continuously. It has a centripetal acceleration acting on it whose magnitude remains constant but the direction which is radially inward changing continuously.


Regards,