Answer: 63 W
Explanation:
Power is defined as the amount of work done divided by the time taken:
[tex]P=\frac{W}{t}[/tex]
where W is the work done, and t is the time taken.
The work done is given by the product between the force applied and the displacement of the bag:
[tex]W=Fd=(21 N)(9 m)=189 J[/tex]
So, the power in this case is
[tex]P=\frac{W}{t}=\frac{189 J}{3 s}=63 W[/tex]
