The work done by the machine is equal to the product between the force applied and the distance over which the force is applieds, so in this case:
[tex]W=Fd=(3 N)(9 m)=27 J[/tex]
And the power of the machine is equal to the ratio between the work done by the machine and the time taken:
[tex]P= \frac{W}{t}= \frac{27 J}{8 s}=3.38 W [/tex]
