ANSWER:
25.87 J
STEP-BY-STEP EXPLANATION:
The work due to gravity in this case would be the weight times the height difference, therefore:
[tex]W=m\cdot g\cdot\Delta h[/tex]We replace and calculate the work like this:
[tex]\begin{gathered} W=2\cdot9.8\cdot(2.1-0.78) \\ W=25.87\text{ J} \end{gathered}[/tex]The work due to gravity is 25.87 J