Light waves can be from any color, depends on what it is bouncing no or reflecting off of.
The width of the playroom is 4 m
Answer:
500ms times 2 would be when the ball reaches the max horizontal distance.
Then to find the angle, use the formula of time to reach max height t = u sin theta / g . With t being the max height time 500ms, u being 10m/s
For initial vertical velocity just use u sin theta.