Response:
The change in potential energy can be expressed as 
Explanation:
It is stated that:
The ball's mass, m = 0.5 kg
Initially it is raised to a height of, h = 2 m
After that, it bounces to a height of 1.8 meters, which gives us the final height, h' = 1.8 m
We can calculate the change in potential energy for the whole process. Let
represent the initial potential energy, which is calculated as:

Now, let
encompass the final potential energy, given by:

Let
denote the change in potential energy, determined by:



Thus, the change in gravitational potential energy equals 0.98 J. Therefore, this is the answer sought.