Yes, the velocity is changing.
Velocity is a quantity composed of the speed and the direction of motion.
Constant velocity means: Constant speed, in a straight line.
If the direction is changing, then the velocity is changing, even if the speed is constant.
You can be accelerating and traveling at a constant speed if you change directions.
If you are traveling at a constant speed with changing direction there is a change in velocity, so you are accelerating.
It has no acceleration. The definition of acceleration is the change in velocity over time, so if it is traveling at a constant speed, it has no acceleration. Also, the speed of light is a constant, which means it does not change.
yes
If a velocity or speed is constant there isn't an acceleration. This is because the acceleration is the change in speed or velocity and if it's constant then there sn't a change.
If your acceleration is zero, then yes, you are traveling at a constant speed. The path does not matter. Acceleration measures the change in velocity, so an acceleration of zero means that there is zero change in velocity and therefore the speed is constant.
No. Acceleration is change of velocity / time. If there is no change in velocity, there is no acceleration.
No, the magnitude will be constant, but the direction of the momentum will change to reflect the direction of the velocity.
No it does not because once you change direction you do not have a constant speed.
Yes, if the acceleration is not colinear with the existing velocity.
When you (or an object) travel without changing speed, then you have constant velocity (speed). This means there is no change in speed (acceleration) when you (or an object) is traveling.
A change in the vector or direction that you are traveling is considered an acceleration; even if you don't change speed. This would be the case for going around in a merry-go-round, e.g. You are accelerating (changing direction), but the speed is constant (velocity is changing).