Frames moving uniformly with respect to an inertial frame are: Inertial frames

If a frame is moving uniformly (i.e., with constant velocity) with respect to an inertial frame, it is also considered an inertial frame.

Here's the reasoning:

• Constant Velocity: When a frame moves with a constant velocity, its acceleration is zero. This is because acceleration is the derivative of velocity with respect to time, and if velocity doesn't change, its derivative (acceleration) is zero.
• No Acceleration: With zero acceleration, the conditions match those of an inertial frame of reference, which is either at rest or moving with a constant velocity relative to another inertial frame.

Thus, frames that are moving with a constant velocity with respect to an inertial frame are themselves called inertial frames.

So the answer is:

Inertial frames