To determine the valid velocity reading for an object among the given options, let's analyze each one step-by-step:
1. 45 m/s: This reading indicates a speed of 45 meters per second without specifying any particular direction. This can be considered a valid velocity as it provides a clear magnitude of the object's motion.
2. 45 m/s north: This reading indicates a speed of 45 meters per second with a specific direction towards the north. While this too is a valid velocity, it may involve additional context about direction which the question may not be asking for.
3. 0 m/s south: This reading indicates the object is stationary since its speed is 0 meters per second, despite indicating a direction. A speed of 0 means there is no motion, so this isn't a valid velocity indicating movement.
4. 0 m/s: Similar to the previous reading, this indicates the object is not moving at all, as its speed is 0 meters per second. Again, this isn't a valid velocity indicating any actual movement.
After reviewing all options, the valid velocity reading is:
45 m/s.
This reading specifies the object's speed without unnecessary additional directional information, fitting the context of what we need to determine.
