Answer: No , he is definitely not
Explanation:
The mule is sitting down, the forces interacting with it vertically are its weight (120kg*9.8m/s^2) which is equal to the normal force  N = 120kg*9.8m/s^2 = 1176N. Horizontally we have the 800N exerted by the farmer minus ms*N (static friction force), according to the theory, in order to move the mule the farmer must satisfy [tex]m_{s} = F_{smax}/N[/tex] which means 0.8*1176N = F[tex]F_{smax}[/tex] = 940 N which is not what the farmer is pulling, therefore, the mule will not move an inch
