Can a body have a constant speed and still have a varying velocity?

When a body moves with constant speed along a circle

A body whose speed is constant :

Water from a sprinkler comes out with a constant velocity u in all the directions. What is the maximum area of the grassland that can be watered at any time?

Give an example of a body possessing zero velocity and still accelerating.

Can the velocity of a body negative or zero ?

Draw the velocity - time graph of a body having initial velocity, when the velocity is non - uniform.

A comet orbits the Sun in a highly elliptical orbit. Does the comet have a constant (a) linear speed, (b) angular speed, (c) angular momentum, (d) kinetic energy, (e) potential energy, (f) total energy throughout its orbit? Neglect any mass loss of the comet when it comes very close to the Sun.

Draw the velocity - time graph of a body having initial velocity, when the velocity is uniform.

Distinguish between average velocity and average speed. Is it possible that the average velocity of a body is zero, but its average speed is non-zero?