The question is an illustration of related rates.
The rate of change between you and the ball is 0.01 rad per second
I added an attachment to illustrate the given parameters.
The representations on the attachment are:
---- the rate
First, we calculate the vertical distance (y) using tangent ratio
Substitute 100 for x
Differentiate both sides with respect to time (t)
Substitute values for the rates and
This gives
Divide both sides by 2
Hence, the rate of change between you and the ball is 0.01 rad per second
Read more about related rates at:
