Answer:
![U = - x^2y - xz^3](https://img.qammunity.org/2020/formulas/physics/middle-school/gym253o6gn7l0hz4jiq3bkw41tx9qwxfy2.png)
since the work done in closed path for above function is independent of the path so this is a conservative field
![W = -204 J](https://img.qammunity.org/2020/formulas/physics/middle-school/kyf9y9aws1ybcxvlozd016anxg3izcil0t.png)
Step-by-step explanation:
As we know that
![F_x = -(dU)/(dx) = 2xy + z^3](https://img.qammunity.org/2020/formulas/physics/middle-school/5d5qbsok41f6r9gfl0b3wlxmtnhj3yd6z7.png)
![F_y = -(dU)/(dy) = x^2](https://img.qammunity.org/2020/formulas/physics/middle-school/ve08770t9bysfjt7k457r2h4bvrvfafmmj.png)
![F_z = -(dU)/(dz) = 3xz^2](https://img.qammunity.org/2020/formulas/physics/middle-school/dw24bl23bwwapp93rxlcwbl9oh2ctqgyjj.png)
now from above 3 equations we have
![U = - x^2y - xz^3](https://img.qammunity.org/2020/formulas/physics/middle-school/gym253o6gn7l0hz4jiq3bkw41tx9qwxfy2.png)
since the work done in closed path for above function is independent of the path
so this is a conservative field
Now work done in moving the object is given as
![W = U_f - U_i](https://img.qammunity.org/2020/formulas/physics/high-school/sbydxkxjger9bgkyazjdqfk7ylzt31fu4s.png)
![W = (- 3^2(1) - 3(4^3) ) - (- (1^2)(-2) - 1(1^3))](https://img.qammunity.org/2020/formulas/physics/middle-school/rx8hugj09523k0kpyzppqecgmejb6149z9.png)
![W = -201 - 3](https://img.qammunity.org/2020/formulas/physics/middle-school/fmlocaiy4w28l0y7q0xcdel41b6qodgbbm.png)