The work done by a force is equal to:
[tex]W=Fd[/tex]
where
W is the work
F is the force applied
d is the distance through which the force is applied.
In our problem, the force needed to lift the dog is equal to the weight of the dog:
F=24 N
and the dog is moved through a distance of
d=4.8 m
therefore, the work done by the child to lift the dog is
[tex]W=Fd=(24 N)(4.8 m)=115.2 J[/tex]
