Answer:
8.8 J
Explanation:
The mechanical energy of the marshmallow + gun system is conserved. At the beginning, all the energy is stored in the compressed spring; when the marshmallow is fired, this energy is converted into gravitational potential energy: so the mechanical energy of the system is equal to the gravitational potential energy of the marshmallow when it is at its highest point. Therefore, it is
[tex]E=U=mgh[/tex]
where
m = 0.05 kg is the mass of the marshmallow
g = 9.8 m/s^2 is the acceleration due to gravity
h = 18 m is the maximum height
Substituting, we find
[tex]U=(0.05 kg)(9.8 m/s^2)(18 m)=8.8 J[/tex]
