Question

In paintings what line and value weights tend to suggest motion

Answer 1

Diagnol lines tend to show motion in art

Answer 2

The answer is:

Diagonal line
Diagonal lines imply movement and direction. These lines are neither vertical nor horizontal. They suggest a feeling of movement or an activity. Unlike diagonal lines, horizontal lines suggest calm and stability and vertical lines suggest authority and strength. In terms of orientation, diagonal elements  carry the most weight.

I hope this helps :D