Agraph shows how the temperature of a substance changes as energy is added steadily over time.
which part of the graph would indicate a phase change is taking place?
a steep, downward sloping line
a flat, horizontal line
a steep, upward sloping line

A flat, horizontal line  

Explanation:

A flat, horizontal line indicates a phase change.

The temperature does not increase because the added heat goes into converting one phase into another.

A is wrong. A downward-sloping line indicates that the temperature is decreasing with time.

C is wrong. An upward-sloping line indicates that the temperature is increasing with time.

if they have a finite resultant

what is the speed of a softball that travels 20m in 2secs

speed = 20/2 = 10 m/s