Which of the following is a complete description of the velocity of an object in motion?

A train travels due west at 90 km/h.

A 7 kg bowling ball rolls a distance of 20 m in 3 s.

A runner jogs 6 km/h for 10 minutes.

Birds fly 600 km south for the winter.

A train travels due west at 90 km/h.

Explanation:

In order to give the complete description of velocity, we need to recall that velocity is a vector quantity. We must have both magnitude and direction for a vector quantity.

Since, velocity is a vector, it should have both magnitude and direction.

The magnitude of velocity is given in km/h or m/s.

Here, only the first option has magnitude of 90 km/h and direction as west.

So, the first option is the correct one.