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.

in cartography, a contour line (often just called a "contour") joins points of equal elevation (height) above a given level, such as mean sea level. a contour map is a map illustrated with contour lines, for example a topographic map, which thus shows valleys and hills, and the steepness or gentleness of slopes.

explanation:

atomic mass = 39

number of neutrons = 20

number of protons= 19

electronic configuration = 1s2 2s2 2p6 3s2 3p6 4s1

the number of electron in first shell = 2

number of electrons in n=3 shell = 8