what is the unit for translational speed? is it the same as m/s or different?

Answer 1

speed is m/s, it is a scalar and you can measure it with a speedometer

velocity is ALSO m/s but is a vector. You need both a speedometer AND a compass to measure it.

speed is the magnitude of the velocity vector.

Answer 2

May be its rad/sec.

Answer 3

NO ! radians per second is angular velocity or speed.
speed = radius * w
where w = angular speed in radians/second and radius is in meters then speed is m/s still
radians has no linear units, just 2pi of them is a circle.