Missing information:
The mass of the object is 15 kg.
Answer:
18.7 m
Explanation:
The gravitational potential energy of an object is given by
[tex]U=mgh[/tex]
where
m is the mass of the object
g is the acceleration of gravity
h is the heigth of the object, relative to the ground
In this problem, we know:
U = 2750 J is the potential energy of the object
[tex]g=9.8 m/s^2[/tex]
m = 15 kg is the mass of the object
Solving for h, we find the height of the shelf:
[tex]h=\frac{U}{mg}=\frac{2750}{(15)(9.8)}=18.7 m[/tex]